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Anatomy_Gray_2400 | Anatomy_Gray | Posterior to the pharynx, the pretracheal layer is referred to as the buccopharyngeal fascia and separates the pharynx from the prevertebral layer (Fig. 8.163). The buccopharyngeal fascia begins superiorly at the base of the skull and merges with fascia covering the esophagus that then continues inferiorly into the thoracic cavity. Each carotid sheath is a column of fascia that surrounds the common carotid artery, the internal carotid artery, the internal jugular vein, and the vagus nerve as these structures pass through the neck (Fig. 8.162). It receives contributions from the investing, prevertebral, and pretracheal layers, though the extent of each component’s contribution varies. The arrangement of the various layers of cervical fascia organizes the neck into four longitudinal compartments (Fig. 8.160): The first compartment is the largest, includes the other three, and consists of the area surrounded by the investing layer. | Anatomy_Gray. Posterior to the pharynx, the pretracheal layer is referred to as the buccopharyngeal fascia and separates the pharynx from the prevertebral layer (Fig. 8.163). The buccopharyngeal fascia begins superiorly at the base of the skull and merges with fascia covering the esophagus that then continues inferiorly into the thoracic cavity. Each carotid sheath is a column of fascia that surrounds the common carotid artery, the internal carotid artery, the internal jugular vein, and the vagus nerve as these structures pass through the neck (Fig. 8.162). It receives contributions from the investing, prevertebral, and pretracheal layers, though the extent of each component’s contribution varies. The arrangement of the various layers of cervical fascia organizes the neck into four longitudinal compartments (Fig. 8.160): The first compartment is the largest, includes the other three, and consists of the area surrounded by the investing layer. |
Anatomy_Gray_2401 | Anatomy_Gray | The first compartment is the largest, includes the other three, and consists of the area surrounded by the investing layer. The second compartment consists of the vertebral column and the deep muscles associated with this structure, and is the area contained within the prevertebral layer. The third compartment (the visceral compartment) contains the pharynx, the trachea, the esophagus, and the thyroid gland, which are surrounded by the pretracheal layer. Finally, there is a compartment (the carotid sheath) consisting of the neurovascular structures that pass from the base of the skull to the thoracic cavity, and the sheath enclosing these structures receives contributions from the other cervical fascias. Between the fascial layers in the neck are spaces that may provide a conduit for the spread of infections from the neck to the mediastinum. (Fig. 8.163): | Anatomy_Gray. The first compartment is the largest, includes the other three, and consists of the area surrounded by the investing layer. The second compartment consists of the vertebral column and the deep muscles associated with this structure, and is the area contained within the prevertebral layer. The third compartment (the visceral compartment) contains the pharynx, the trachea, the esophagus, and the thyroid gland, which are surrounded by the pretracheal layer. Finally, there is a compartment (the carotid sheath) consisting of the neurovascular structures that pass from the base of the skull to the thoracic cavity, and the sheath enclosing these structures receives contributions from the other cervical fascias. Between the fascial layers in the neck are spaces that may provide a conduit for the spread of infections from the neck to the mediastinum. (Fig. 8.163): |
Anatomy_Gray_2402 | Anatomy_Gray | Between the fascial layers in the neck are spaces that may provide a conduit for the spread of infections from the neck to the mediastinum. (Fig. 8.163): The first is the pretracheal space between the investing layer of cervical fascia covering the posterior surface of the infrahyoid muscles and the pretracheal fascia (covering the anterior surface of the trachea and the thyroid gland), which passes between the neck and the anterior part of the superior mediastinum. The second is the retropharyngeal space between the buccopharyngeal fascia (on the posterior surface of the pharynx and esophagus) and the prevertebral fascia (on the anterior surface of the transverse processes and bodies of the cervical vertebrae), which extends from the base of the skull to the upper part of the posterior mediastinum. | Anatomy_Gray. Between the fascial layers in the neck are spaces that may provide a conduit for the spread of infections from the neck to the mediastinum. (Fig. 8.163): The first is the pretracheal space between the investing layer of cervical fascia covering the posterior surface of the infrahyoid muscles and the pretracheal fascia (covering the anterior surface of the trachea and the thyroid gland), which passes between the neck and the anterior part of the superior mediastinum. The second is the retropharyngeal space between the buccopharyngeal fascia (on the posterior surface of the pharynx and esophagus) and the prevertebral fascia (on the anterior surface of the transverse processes and bodies of the cervical vertebrae), which extends from the base of the skull to the upper part of the posterior mediastinum. |
Anatomy_Gray_2403 | Anatomy_Gray | The third space is within the prevertebral layer covering the anterior surface of the transverse processes and bodies of the cervical vertebrae. This layer splits into two laminae to create a fascial space that begins at the base of the skull and extends through the posterior mediastinum to the diaphragm. The external jugular and anterior jugular veins are the primary venous channels for superficial venous drainage of the neck (Fig. 8.164). The external jugular vein is formed posterior to the angle of the mandible as the posterior auricular vein and the retromandibular vein join: The posterior auricular vein drains the scalp behind and above the ear. | Anatomy_Gray. The third space is within the prevertebral layer covering the anterior surface of the transverse processes and bodies of the cervical vertebrae. This layer splits into two laminae to create a fascial space that begins at the base of the skull and extends through the posterior mediastinum to the diaphragm. The external jugular and anterior jugular veins are the primary venous channels for superficial venous drainage of the neck (Fig. 8.164). The external jugular vein is formed posterior to the angle of the mandible as the posterior auricular vein and the retromandibular vein join: The posterior auricular vein drains the scalp behind and above the ear. |
Anatomy_Gray_2404 | Anatomy_Gray | The posterior auricular vein drains the scalp behind and above the ear. The retromandibular vein is formed when the superficial temporal and maxillary veins join in the substance of the parotid gland and it descends to the angle of mandible, where it divides into an anterior and a posterior division (Fig. 8.164)—the posterior division joins the posterior auricular vein to form the external jugular vein, and the anterior division joins the facial vein to form the common facial vein, which passes deep and becomes a tributary to the internal jugular vein. Once formed, the external jugular vein passes straight down the neck in the superficial fascia and is superficial to the sternocleidomastoid muscle throughout its course, crossing it diagonally as it descends. | Anatomy_Gray. The posterior auricular vein drains the scalp behind and above the ear. The retromandibular vein is formed when the superficial temporal and maxillary veins join in the substance of the parotid gland and it descends to the angle of mandible, where it divides into an anterior and a posterior division (Fig. 8.164)—the posterior division joins the posterior auricular vein to form the external jugular vein, and the anterior division joins the facial vein to form the common facial vein, which passes deep and becomes a tributary to the internal jugular vein. Once formed, the external jugular vein passes straight down the neck in the superficial fascia and is superficial to the sternocleidomastoid muscle throughout its course, crossing it diagonally as it descends. |
Anatomy_Gray_2405 | Anatomy_Gray | Reaching the lower part of the neck, just superior to the clavicle and immediately posterior to the sternocleidomastoid muscle, the external jugular vein pierces the investing layer of cervical fascia, passes deep to the clavicle, and enters the subclavian vein. Tributaries received by the external jugular vein along its course include the posterior external jugular vein (draining superficial areas of the back of the neck) and the transverse cervical and suprascapular veins (draining the posterior scapular region). The anterior jugular veins, although variable and inconsistent, are usually described as draining the anterior aspect of the neck (Fig. 8.164). These paired venous channels, which begin as small veins, come together at or just superior to the hyoid bone. Once formed, each anterior jugular vein descends on either side of the midline of the neck. | Anatomy_Gray. Reaching the lower part of the neck, just superior to the clavicle and immediately posterior to the sternocleidomastoid muscle, the external jugular vein pierces the investing layer of cervical fascia, passes deep to the clavicle, and enters the subclavian vein. Tributaries received by the external jugular vein along its course include the posterior external jugular vein (draining superficial areas of the back of the neck) and the transverse cervical and suprascapular veins (draining the posterior scapular region). The anterior jugular veins, although variable and inconsistent, are usually described as draining the anterior aspect of the neck (Fig. 8.164). These paired venous channels, which begin as small veins, come together at or just superior to the hyoid bone. Once formed, each anterior jugular vein descends on either side of the midline of the neck. |
Anatomy_Gray_2406 | Anatomy_Gray | Inferiorly, near the medial attachment of the sternocleidomastoid muscle, each anterior jugular vein pierces the investing layer of cervical fascia to enter the subclavian vein. Occasionally, the anterior jugular vein may enter the external jugular vein immediately before the external jugular vein enters the subclavian vein. Often, the right and left anterior jugular veins communicate with each other, being connected by a jugular venous arch in the area of the suprasternal notch. Anterior triangle of the neck The anterior triangle of the neck is outlined by the anterior border of the sternocleidomastoid muscle laterally, the inferior border of the mandible superiorly, and the midline of the neck medially (Fig. 8.166). It is further subdivided into several smaller triangles as follows: The submandibular triangle is outlined by the inferior border of the mandible superiorly and the anterior and posterior bellies of the digastric muscle inferiorly. | Anatomy_Gray. Inferiorly, near the medial attachment of the sternocleidomastoid muscle, each anterior jugular vein pierces the investing layer of cervical fascia to enter the subclavian vein. Occasionally, the anterior jugular vein may enter the external jugular vein immediately before the external jugular vein enters the subclavian vein. Often, the right and left anterior jugular veins communicate with each other, being connected by a jugular venous arch in the area of the suprasternal notch. Anterior triangle of the neck The anterior triangle of the neck is outlined by the anterior border of the sternocleidomastoid muscle laterally, the inferior border of the mandible superiorly, and the midline of the neck medially (Fig. 8.166). It is further subdivided into several smaller triangles as follows: The submandibular triangle is outlined by the inferior border of the mandible superiorly and the anterior and posterior bellies of the digastric muscle inferiorly. |
Anatomy_Gray_2407 | Anatomy_Gray | The submandibular triangle is outlined by the inferior border of the mandible superiorly and the anterior and posterior bellies of the digastric muscle inferiorly. The submental triangle is outlined by the hyoid bone inferiorly, the anterior belly of the digastric muscle laterally, and the midline. The muscular triangle is outlined by the hyoid bone superiorly, the superior belly of the omohyoid muscle, and the anterior border of the sternocleidomastoid muscle laterally, and the midline. The carotid triangle is outlined by the superior belly of the omohyoid muscle anteroinferiorly, the stylohyoid muscle and posterior belly of the digastric superiorly, and the anterior border of the sternocleidomastoid muscle posteriorly. | Anatomy_Gray. The submandibular triangle is outlined by the inferior border of the mandible superiorly and the anterior and posterior bellies of the digastric muscle inferiorly. The submental triangle is outlined by the hyoid bone inferiorly, the anterior belly of the digastric muscle laterally, and the midline. The muscular triangle is outlined by the hyoid bone superiorly, the superior belly of the omohyoid muscle, and the anterior border of the sternocleidomastoid muscle laterally, and the midline. The carotid triangle is outlined by the superior belly of the omohyoid muscle anteroinferiorly, the stylohyoid muscle and posterior belly of the digastric superiorly, and the anterior border of the sternocleidomastoid muscle posteriorly. |
Anatomy_Gray_2408 | Anatomy_Gray | Each of these triangles contains numerous structures that can be identified as being within a specific triangle, passing into a specific triangle from outside the area, originating in one triangle and passing to another triangle, or passing through several triangles while passing through the region. A discussion of the anterior triangle of the neck must therefore combine a systemic approach, describing the muscles, vessels, and nerves in the area, with a regional approach, describing the contents of each triangle. The muscles in the anterior triangle of the neck (Table 8.12) can be grouped according to their location relative to the hyoid bone: Muscles superior to the hyoid are classified as suprahyoid muscles and include the stylohyoid, digastric, mylohyoid, and geniohyoid. Muscles inferior to the hyoid are infrahyoid muscles and include the omohyoid, sternohyoid, thyrohyoid, and sternothyroid. | Anatomy_Gray. Each of these triangles contains numerous structures that can be identified as being within a specific triangle, passing into a specific triangle from outside the area, originating in one triangle and passing to another triangle, or passing through several triangles while passing through the region. A discussion of the anterior triangle of the neck must therefore combine a systemic approach, describing the muscles, vessels, and nerves in the area, with a regional approach, describing the contents of each triangle. The muscles in the anterior triangle of the neck (Table 8.12) can be grouped according to their location relative to the hyoid bone: Muscles superior to the hyoid are classified as suprahyoid muscles and include the stylohyoid, digastric, mylohyoid, and geniohyoid. Muscles inferior to the hyoid are infrahyoid muscles and include the omohyoid, sternohyoid, thyrohyoid, and sternothyroid. |
Anatomy_Gray_2409 | Anatomy_Gray | Muscles inferior to the hyoid are infrahyoid muscles and include the omohyoid, sternohyoid, thyrohyoid, and sternothyroid. The four pairs of suprahyoid muscles are related to the submental and submandibular triangles (Fig. 8.166). They pass in a superior direction from the hyoid bone to the skull or mandible and raise the hyoid, as occurs during swallowing. The stylohyoid muscle arises from the base of the styloid process and passes anteroinferiorly to attach to the lateral area of the body of the hyoid bone (Fig. 8.167). During swallowing it pulls the hyoid bone posterosuperiorly and it is innervated by the facial nerve [VII]. The digastric muscle has two bellies connected by a tendon, which attaches to the body of the hyoid bone (Fig. 8.167): The posterior belly arises from the mastoid notch on the medial side of the mastoid process of the temporal bone. The anterior belly arises from the digastric fossa on the lower inside of the mandible. | Anatomy_Gray. Muscles inferior to the hyoid are infrahyoid muscles and include the omohyoid, sternohyoid, thyrohyoid, and sternothyroid. The four pairs of suprahyoid muscles are related to the submental and submandibular triangles (Fig. 8.166). They pass in a superior direction from the hyoid bone to the skull or mandible and raise the hyoid, as occurs during swallowing. The stylohyoid muscle arises from the base of the styloid process and passes anteroinferiorly to attach to the lateral area of the body of the hyoid bone (Fig. 8.167). During swallowing it pulls the hyoid bone posterosuperiorly and it is innervated by the facial nerve [VII]. The digastric muscle has two bellies connected by a tendon, which attaches to the body of the hyoid bone (Fig. 8.167): The posterior belly arises from the mastoid notch on the medial side of the mastoid process of the temporal bone. The anterior belly arises from the digastric fossa on the lower inside of the mandible. |
Anatomy_Gray_2410 | Anatomy_Gray | The anterior belly arises from the digastric fossa on the lower inside of the mandible. The tendon between the two bellies, which is attached to the body of the hyoid bone, is the point of insertion of both bellies. Because of this arrangement, the muscle has multiple actions depending on which bone is fixed: When the mandible is fixed, the digastric muscle raises the hyoid bone. When the hyoid bone is fixed, the digastric muscle opens the mouth by lowering the mandible. Innervation of the digastric muscle is from two different cranial nerves. The innervation of the posterior belly of the digastric muscle is by the facial nerve [VII], whereas the anterior belly of the muscle is innervated by the mandibular division [V3] of the trigeminal nerve [V]. | Anatomy_Gray. The anterior belly arises from the digastric fossa on the lower inside of the mandible. The tendon between the two bellies, which is attached to the body of the hyoid bone, is the point of insertion of both bellies. Because of this arrangement, the muscle has multiple actions depending on which bone is fixed: When the mandible is fixed, the digastric muscle raises the hyoid bone. When the hyoid bone is fixed, the digastric muscle opens the mouth by lowering the mandible. Innervation of the digastric muscle is from two different cranial nerves. The innervation of the posterior belly of the digastric muscle is by the facial nerve [VII], whereas the anterior belly of the muscle is innervated by the mandibular division [V3] of the trigeminal nerve [V]. |
Anatomy_Gray_2411 | Anatomy_Gray | The mylohyoid muscle is superior to the anterior belly of the digastric and, with its partner from the opposite side, forms the floor of the mouth (Fig. 8.167). It originates from the mylohyoid line on the medial surface of the body of the mandible and inserts into the hyoid bone and also blends with the mylohyoid muscle from the opposite side. This mylohyoid muscle supports and elevates the floor of the mouth and elevates the hyoid bone. It is innervated by the mandibular division [V3] of the trigeminal nerve [V]. The geniohyoid muscle is superior to the floor of the oral cavity and is not generally considered a muscle of the anterior triangle of the neck; however, it can be regarded as a suprahyoid muscle. It is the final muscle in the suprahyoid group (Fig. 8.167). A narrow muscle, it is superior to the medial part of each mylohyoid muscle. The muscles from each side are next to each other in the midline. | Anatomy_Gray. The mylohyoid muscle is superior to the anterior belly of the digastric and, with its partner from the opposite side, forms the floor of the mouth (Fig. 8.167). It originates from the mylohyoid line on the medial surface of the body of the mandible and inserts into the hyoid bone and also blends with the mylohyoid muscle from the opposite side. This mylohyoid muscle supports and elevates the floor of the mouth and elevates the hyoid bone. It is innervated by the mandibular division [V3] of the trigeminal nerve [V]. The geniohyoid muscle is superior to the floor of the oral cavity and is not generally considered a muscle of the anterior triangle of the neck; however, it can be regarded as a suprahyoid muscle. It is the final muscle in the suprahyoid group (Fig. 8.167). A narrow muscle, it is superior to the medial part of each mylohyoid muscle. The muscles from each side are next to each other in the midline. |
Anatomy_Gray_2412 | Anatomy_Gray | The geniohyoid arises from the inferior mental spine of the mandible and passes backward and downward to insert on the body of the hyoid bone. It has two functions depending on which bone is fixed: Fixation of the mandible elevates and pulls the hyoid bone forward. Fixation of the hyoid bone pulls the mandible downward and inward. The geniohyoid is innervated by a branch from the anterior ramus of C1 carried along the hypoglossal nerve [XII]. The four infrahyoid muscles are related to the muscular triangle (Fig. 8.166). They attach the hyoid bone to inferior structures and depress the hyoid bone. They also provide a stable point of attachment for the suprahyoid muscles. Because of their appearance, they are sometimes referred to as the “strap muscles.” | Anatomy_Gray. The geniohyoid arises from the inferior mental spine of the mandible and passes backward and downward to insert on the body of the hyoid bone. It has two functions depending on which bone is fixed: Fixation of the mandible elevates and pulls the hyoid bone forward. Fixation of the hyoid bone pulls the mandible downward and inward. The geniohyoid is innervated by a branch from the anterior ramus of C1 carried along the hypoglossal nerve [XII]. The four infrahyoid muscles are related to the muscular triangle (Fig. 8.166). They attach the hyoid bone to inferior structures and depress the hyoid bone. They also provide a stable point of attachment for the suprahyoid muscles. Because of their appearance, they are sometimes referred to as the “strap muscles.” |
Anatomy_Gray_2413 | Anatomy_Gray | The sternohyoid muscle is a long, thin muscle originating from the posterior aspect of the sternoclavicular joint and adjacent manubrium of the sternum (Fig. 8.168). It ascends to insert onto the body of the hyoid bone. It depresses the hyoid bone and is innervated by the anterior rami of C1 to C3 through the ansa cervicalis. Lateral to the sternohyoid muscle is the omohyoid muscle (Fig. 8.168). This muscle consists of two bellies with an intermediate tendon in both the posterior and anterior triangles of the neck: The inferior belly begins on the superior border of the scapula, medial to the suprascapular notch, and passes forward and upward across the posterior triangle ending at the intermediate tendon. The superior belly begins at the intermediate tendon and ascends to attach to the body of the hyoid bone just lateral to the attachment of the sternohyoid. The intermediate tendon is attached to the clavicle, near its medial end, by a fascial sling. | Anatomy_Gray. The sternohyoid muscle is a long, thin muscle originating from the posterior aspect of the sternoclavicular joint and adjacent manubrium of the sternum (Fig. 8.168). It ascends to insert onto the body of the hyoid bone. It depresses the hyoid bone and is innervated by the anterior rami of C1 to C3 through the ansa cervicalis. Lateral to the sternohyoid muscle is the omohyoid muscle (Fig. 8.168). This muscle consists of two bellies with an intermediate tendon in both the posterior and anterior triangles of the neck: The inferior belly begins on the superior border of the scapula, medial to the suprascapular notch, and passes forward and upward across the posterior triangle ending at the intermediate tendon. The superior belly begins at the intermediate tendon and ascends to attach to the body of the hyoid bone just lateral to the attachment of the sternohyoid. The intermediate tendon is attached to the clavicle, near its medial end, by a fascial sling. |
Anatomy_Gray_2414 | Anatomy_Gray | The intermediate tendon is attached to the clavicle, near its medial end, by a fascial sling. The omohyoid depresses and fixes the hyoid bone. It is innervated by the anterior rami of C1 to C3 through the ansa cervicalis. The thyrohyoid muscle is deep to the superior parts of the omohyoid and sternohyoid (Fig. 8.168). Originating at the oblique line on the lamina of the thyroid cartilage it passes upward to insert into the greater horn and adjacent aspect of the body of the hyoid bone. The thyrohyoid muscle has variable functions depending on which bone is fixed. Generally, it depresses the hyoid, but when the hyoid is fixed it raises the larynx (e.g., when high notes are sung). It is innervated by fibers from the anterior ramus of C1 that travel with the hypoglossal nerve [XII]. | Anatomy_Gray. The intermediate tendon is attached to the clavicle, near its medial end, by a fascial sling. The omohyoid depresses and fixes the hyoid bone. It is innervated by the anterior rami of C1 to C3 through the ansa cervicalis. The thyrohyoid muscle is deep to the superior parts of the omohyoid and sternohyoid (Fig. 8.168). Originating at the oblique line on the lamina of the thyroid cartilage it passes upward to insert into the greater horn and adjacent aspect of the body of the hyoid bone. The thyrohyoid muscle has variable functions depending on which bone is fixed. Generally, it depresses the hyoid, but when the hyoid is fixed it raises the larynx (e.g., when high notes are sung). It is innervated by fibers from the anterior ramus of C1 that travel with the hypoglossal nerve [XII]. |
Anatomy_Gray_2415 | Anatomy_Gray | Lying beneath the sternohyoid and in continuity with the thyrohyoid, the sternothyroid is the last muscle in the infrahyoid group (Fig. 8.168). It arises from the posterior surface of the manubrium of the sternum and passes upward to attach to the oblique line on the lamina of the thyroid cartilage. The sternothyroid muscle draws the larynx (thyroid cartilage) downward and is innervated by the anterior rami of C1 to C3 through the ansa cervicalis. Passing through the anterior triangle of the neck are the common carotid arteries and their branches, the external and internal carotid arteries. These vessels supply all structures of the head and neck. Associated with this arterial system are the internal jugular vein and its tributaries. These vessels receive blood from all structures of the head and neck. The common carotid arteries are the beginning of the carotid system (Fig. 8.169): | Anatomy_Gray. Lying beneath the sternohyoid and in continuity with the thyrohyoid, the sternothyroid is the last muscle in the infrahyoid group (Fig. 8.168). It arises from the posterior surface of the manubrium of the sternum and passes upward to attach to the oblique line on the lamina of the thyroid cartilage. The sternothyroid muscle draws the larynx (thyroid cartilage) downward and is innervated by the anterior rami of C1 to C3 through the ansa cervicalis. Passing through the anterior triangle of the neck are the common carotid arteries and their branches, the external and internal carotid arteries. These vessels supply all structures of the head and neck. Associated with this arterial system are the internal jugular vein and its tributaries. These vessels receive blood from all structures of the head and neck. The common carotid arteries are the beginning of the carotid system (Fig. 8.169): |
Anatomy_Gray_2416 | Anatomy_Gray | The common carotid arteries are the beginning of the carotid system (Fig. 8.169): The right common carotid artery originates from the brachiocephalic trunk immediately posterior to the right sternoclavicular joint and is entirely in the neck throughout its course. The left common carotid artery begins in the thorax as a direct branch of the arch of the aorta and passes superiorly to enter the neck near the left sternoclavicular joint. Both right and left common carotid arteries ascend through the neck, just lateral to the trachea and esophagus, within a fascial compartment (the carotid sheath). They give off no branches as they pass through the neck. Near the superior edge of the thyroid cartilage each common carotid artery divides into its two terminal branches—the external and internal carotid arteries (Fig. 8.170). | Anatomy_Gray. The common carotid arteries are the beginning of the carotid system (Fig. 8.169): The right common carotid artery originates from the brachiocephalic trunk immediately posterior to the right sternoclavicular joint and is entirely in the neck throughout its course. The left common carotid artery begins in the thorax as a direct branch of the arch of the aorta and passes superiorly to enter the neck near the left sternoclavicular joint. Both right and left common carotid arteries ascend through the neck, just lateral to the trachea and esophagus, within a fascial compartment (the carotid sheath). They give off no branches as they pass through the neck. Near the superior edge of the thyroid cartilage each common carotid artery divides into its two terminal branches—the external and internal carotid arteries (Fig. 8.170). |
Anatomy_Gray_2417 | Anatomy_Gray | Near the superior edge of the thyroid cartilage each common carotid artery divides into its two terminal branches—the external and internal carotid arteries (Fig. 8.170). The superior part of each common carotid artery and its division into external and internal carotid arteries occurs in the carotid triangle (Fig. 8.170), which is a subdivision of the anterior triangle of the neck (see Fig. 8.166). At the bifurcation, the common carotid artery and the beginning of the internal carotid artery are dilated. This dilation is the carotid sinus (Fig. 8.171) and contains receptors that monitor changes in blood pressure and are innervated by a branch of the glossopharyngeal nerve [IX]. Another accumulation of receptors in the area of the bifurcation is responsible for detecting changes in blood chemistry, primarily oxygen content. This is the carotid body and is innervated by branches from both the glossopharyngeal [IX] and vagus [X] nerves. | Anatomy_Gray. Near the superior edge of the thyroid cartilage each common carotid artery divides into its two terminal branches—the external and internal carotid arteries (Fig. 8.170). The superior part of each common carotid artery and its division into external and internal carotid arteries occurs in the carotid triangle (Fig. 8.170), which is a subdivision of the anterior triangle of the neck (see Fig. 8.166). At the bifurcation, the common carotid artery and the beginning of the internal carotid artery are dilated. This dilation is the carotid sinus (Fig. 8.171) and contains receptors that monitor changes in blood pressure and are innervated by a branch of the glossopharyngeal nerve [IX]. Another accumulation of receptors in the area of the bifurcation is responsible for detecting changes in blood chemistry, primarily oxygen content. This is the carotid body and is innervated by branches from both the glossopharyngeal [IX] and vagus [X] nerves. |
Anatomy_Gray_2418 | Anatomy_Gray | After its origin, the internal carotid artery ascends toward the base of the skull (Fig. 8.171). It gives off no branches in the neck and enters the cranial cavity through the carotid canal in the petrous part of the temporal bone. The internal carotid arteries supply the cerebral hemispheres, the eyes and the contents of the orbits, and the forehead. The external carotid arteries begin giving off branches immediately after the bifurcation of the common carotid arteries (Fig. 8.171 and Table 8.13) as follows: The superior thyroid artery is the first branch—it arises from the anterior surface near or at the bifurcation and passes in a downward and forward direction to reach the superior pole of the thyroid gland. The ascending pharyngeal artery is the second and smallest branch—it arises from the posterior aspect of the external carotid artery and ascends between the internal carotid artery and the pharynx. | Anatomy_Gray. After its origin, the internal carotid artery ascends toward the base of the skull (Fig. 8.171). It gives off no branches in the neck and enters the cranial cavity through the carotid canal in the petrous part of the temporal bone. The internal carotid arteries supply the cerebral hemispheres, the eyes and the contents of the orbits, and the forehead. The external carotid arteries begin giving off branches immediately after the bifurcation of the common carotid arteries (Fig. 8.171 and Table 8.13) as follows: The superior thyroid artery is the first branch—it arises from the anterior surface near or at the bifurcation and passes in a downward and forward direction to reach the superior pole of the thyroid gland. The ascending pharyngeal artery is the second and smallest branch—it arises from the posterior aspect of the external carotid artery and ascends between the internal carotid artery and the pharynx. |
Anatomy_Gray_2419 | Anatomy_Gray | The ascending pharyngeal artery is the second and smallest branch—it arises from the posterior aspect of the external carotid artery and ascends between the internal carotid artery and the pharynx. The lingual artery arises from the anterior surface of the external carotid artery just above the superior thyroid artery at the level of the hyoid bone, passes deep to the hypoglossal nerve [XII], and passes between the middle constrictor of the pharynx and hyoglossus muscles. The facial artery is the third anterior branch of the external carotid artery—it arises just above the lingual artery, passes deep to the stylohyoid and posterior belly of the digastric muscles, continues deep between the submandibular gland and mandible, and emerges over the edge of the mandible just anterior to the masseter muscle, to enter the face. | Anatomy_Gray. The ascending pharyngeal artery is the second and smallest branch—it arises from the posterior aspect of the external carotid artery and ascends between the internal carotid artery and the pharynx. The lingual artery arises from the anterior surface of the external carotid artery just above the superior thyroid artery at the level of the hyoid bone, passes deep to the hypoglossal nerve [XII], and passes between the middle constrictor of the pharynx and hyoglossus muscles. The facial artery is the third anterior branch of the external carotid artery—it arises just above the lingual artery, passes deep to the stylohyoid and posterior belly of the digastric muscles, continues deep between the submandibular gland and mandible, and emerges over the edge of the mandible just anterior to the masseter muscle, to enter the face. |
Anatomy_Gray_2420 | Anatomy_Gray | The occipital artery arises from the posterior surface of the external carotid artery, near the level of origin of the facial artery, passes upward and posteriorly deep to the posterior belly of the digastric muscle, and emerges on the posterior aspect of the scalp. The posterior auricular artery is a small branch arising from the posterior surface of the external carotid artery and passes upward and posteriorly. The superficial temporal artery is one of the terminal branches and appears as an upward continuation of the external carotid artery—beginning posterior to the neck of the mandible, it passes anterior to the ear, crosses the zygomatic process of the temporal bone, and above this point divides into anterior and posterior branches. | Anatomy_Gray. The occipital artery arises from the posterior surface of the external carotid artery, near the level of origin of the facial artery, passes upward and posteriorly deep to the posterior belly of the digastric muscle, and emerges on the posterior aspect of the scalp. The posterior auricular artery is a small branch arising from the posterior surface of the external carotid artery and passes upward and posteriorly. The superficial temporal artery is one of the terminal branches and appears as an upward continuation of the external carotid artery—beginning posterior to the neck of the mandible, it passes anterior to the ear, crosses the zygomatic process of the temporal bone, and above this point divides into anterior and posterior branches. |
Anatomy_Gray_2421 | Anatomy_Gray | The maxillary artery is the larger of the two terminal branches of the external carotid artery—arising posterior to the neck of the mandible, it passes through the parotid gland, continues medial to the neck of the mandible and into the infratemporal fossa, and continues through this area into the pterygopalatine fossa. Collecting blood from the skull, brain, superficial face, and parts of the neck, the internal jugular vein begins as a dilated continuation of the sigmoid sinus, which is a dural venous sinus. This initial dilated part is referred to as the superior bulb of jugular vein and receives another dural venous sinus (the inferior petrosal sinus) soon after it is formed. It exits the skull through the jugular foramen associated with the glossopharyngeal [IX], vagus [X], and accessory [XI] nerves, and enters the carotid sheath. | Anatomy_Gray. The maxillary artery is the larger of the two terminal branches of the external carotid artery—arising posterior to the neck of the mandible, it passes through the parotid gland, continues medial to the neck of the mandible and into the infratemporal fossa, and continues through this area into the pterygopalatine fossa. Collecting blood from the skull, brain, superficial face, and parts of the neck, the internal jugular vein begins as a dilated continuation of the sigmoid sinus, which is a dural venous sinus. This initial dilated part is referred to as the superior bulb of jugular vein and receives another dural venous sinus (the inferior petrosal sinus) soon after it is formed. It exits the skull through the jugular foramen associated with the glossopharyngeal [IX], vagus [X], and accessory [XI] nerves, and enters the carotid sheath. |
Anatomy_Gray_2422 | Anatomy_Gray | The internal jugular vein traverses the neck within the carotid sheath, initially posterior to the internal carotid artery, but passes to a more lateral position farther down. It remains lateral to the common carotid artery through the rest of the neck with the vagus nerve [X] posterior and partially between the two vessels. The paired internal jugular veins join with the subclavian veins posterior to the sternal end of the clavicle to form the right and left brachiocephalic veins (Fig. 8.169). Tributaries to each internal jugular vein include the inferior petrosal sinus, and the facial, lingual, pharyngeal, occipital, superior thyroid, and middle thyroid veins. Numerous cranial and peripheral nerves: pass through the anterior triangle of the neck as they continue to their final destination, send branches to structures in or forming boundaries of the anterior triangle of the neck, and while in the anterior triangle of the neck, send branches to nearby structures. | Anatomy_Gray. The internal jugular vein traverses the neck within the carotid sheath, initially posterior to the internal carotid artery, but passes to a more lateral position farther down. It remains lateral to the common carotid artery through the rest of the neck with the vagus nerve [X] posterior and partially between the two vessels. The paired internal jugular veins join with the subclavian veins posterior to the sternal end of the clavicle to form the right and left brachiocephalic veins (Fig. 8.169). Tributaries to each internal jugular vein include the inferior petrosal sinus, and the facial, lingual, pharyngeal, occipital, superior thyroid, and middle thyroid veins. Numerous cranial and peripheral nerves: pass through the anterior triangle of the neck as they continue to their final destination, send branches to structures in or forming boundaries of the anterior triangle of the neck, and while in the anterior triangle of the neck, send branches to nearby structures. |
Anatomy_Gray_2423 | Anatomy_Gray | The cranial nerves in these categories include the facial [VII], glossopharyngeal [IX], vagus [X], accessory [XI], and hypoglossal [XII]. Branches of spinal nerves in these categories include the transverse cervical nerve from the cervical plexus and the upper and lower roots of the ansa cervicalis. After emerging from the stylomastoid foramen, the facial nerve [VII] gives off branches that innervate two muscles associated with the anterior triangle of the neck: the posterior belly of the digastric, and the stylohyoid. The facial nerve [VII] also innervates the platysma muscle that overlies the anterior triangle and part of the posterior triangle of the neck. | Anatomy_Gray. The cranial nerves in these categories include the facial [VII], glossopharyngeal [IX], vagus [X], accessory [XI], and hypoglossal [XII]. Branches of spinal nerves in these categories include the transverse cervical nerve from the cervical plexus and the upper and lower roots of the ansa cervicalis. After emerging from the stylomastoid foramen, the facial nerve [VII] gives off branches that innervate two muscles associated with the anterior triangle of the neck: the posterior belly of the digastric, and the stylohyoid. The facial nerve [VII] also innervates the platysma muscle that overlies the anterior triangle and part of the posterior triangle of the neck. |
Anatomy_Gray_2424 | Anatomy_Gray | The facial nerve [VII] also innervates the platysma muscle that overlies the anterior triangle and part of the posterior triangle of the neck. The glossopharyngeal nerve [IX] leaves the cranial cavity through the jugular foramen. It begins its descent between the internal carotid artery and the internal jugular vein, lying deep to the styloid process and the muscles associated with the styloid process. As the glossopharyngeal nerve [IX] completes its descent, it passes forward between the internal and external carotid arteries, and curves around the lateral border of the stylopharyngeus muscle (Fig. 8.172). At this point, it continues in an anterior direction, deep to the hyoglossus muscle, to reach the base of the tongue and the area of the palatine tonsil. As the glossopharyngeal nerve [IX] passes through the area of the anterior triangle of the neck it innervates the stylopharyngeus muscle, sends a branch to the carotid sinus, and supplies sensory branches to the pharynx. | Anatomy_Gray. The facial nerve [VII] also innervates the platysma muscle that overlies the anterior triangle and part of the posterior triangle of the neck. The glossopharyngeal nerve [IX] leaves the cranial cavity through the jugular foramen. It begins its descent between the internal carotid artery and the internal jugular vein, lying deep to the styloid process and the muscles associated with the styloid process. As the glossopharyngeal nerve [IX] completes its descent, it passes forward between the internal and external carotid arteries, and curves around the lateral border of the stylopharyngeus muscle (Fig. 8.172). At this point, it continues in an anterior direction, deep to the hyoglossus muscle, to reach the base of the tongue and the area of the palatine tonsil. As the glossopharyngeal nerve [IX] passes through the area of the anterior triangle of the neck it innervates the stylopharyngeus muscle, sends a branch to the carotid sinus, and supplies sensory branches to the pharynx. |
Anatomy_Gray_2425 | Anatomy_Gray | The vagus nerve [X] exits the cranial cavity through the jugular foramen between the glossopharyngeal [IX] and accessory [XI] nerves. Outside the skull the vagus nerve [X] enters the carotid sheath and descends through the neck enclosed in this structure medial to the internal jugular vein and posterior to the internal carotid and common carotid arteries (Fig. 8.173). Branches of the vagus nerve [X] as it passes through the anterior triangle of the neck include a motor branch to the pharynx, a branch to the carotid body, the superior laryngeal nerve (which divides into external and internal laryngeal branches), and possibly a cardiac branch. | Anatomy_Gray. The vagus nerve [X] exits the cranial cavity through the jugular foramen between the glossopharyngeal [IX] and accessory [XI] nerves. Outside the skull the vagus nerve [X] enters the carotid sheath and descends through the neck enclosed in this structure medial to the internal jugular vein and posterior to the internal carotid and common carotid arteries (Fig. 8.173). Branches of the vagus nerve [X] as it passes through the anterior triangle of the neck include a motor branch to the pharynx, a branch to the carotid body, the superior laryngeal nerve (which divides into external and internal laryngeal branches), and possibly a cardiac branch. |
Anatomy_Gray_2426 | Anatomy_Gray | The accessory nerve [XI] is the most posterior of the three cranial nerves exiting the cranial cavity through the jugular foramen. It begins its descent medial to the internal jugular vein, emerging from between the internal jugular vein and internal carotid artery to cross the lateral surface of the internal jugular vein as it passes downward and backward to disappear either into or beneath the anterior border of the sternocleidomastoid muscle (Fig. 8.174). The accessory nerve gives off no branches as it passes through the anterior triangle of the neck. | Anatomy_Gray. The accessory nerve [XI] is the most posterior of the three cranial nerves exiting the cranial cavity through the jugular foramen. It begins its descent medial to the internal jugular vein, emerging from between the internal jugular vein and internal carotid artery to cross the lateral surface of the internal jugular vein as it passes downward and backward to disappear either into or beneath the anterior border of the sternocleidomastoid muscle (Fig. 8.174). The accessory nerve gives off no branches as it passes through the anterior triangle of the neck. |
Anatomy_Gray_2427 | Anatomy_Gray | The accessory nerve gives off no branches as it passes through the anterior triangle of the neck. The hypoglossal nerve [XII] leaves the cranial cavity through the hypoglossal canal and is medial to the internal jugular vein and internal carotid artery immediately outside the skull. As it descends, it passes outward between the internal jugular vein and internal carotid artery (Fig. 8.175). At this point it passes forward, hooking around the occipital artery, across the lateral surfaces of the internal and external carotid arteries and the lingual artery, and then continues deep to the posterior belly of the digastric and stylohyoid muscles. It passes over the surface of the hyoglossus muscle and disappears deep to the mylohyoid muscle. The hypoglossal nerve [XII], which supplies the tongue, does not give off any branches as it passes through the anterior triangle of the neck. | Anatomy_Gray. The accessory nerve gives off no branches as it passes through the anterior triangle of the neck. The hypoglossal nerve [XII] leaves the cranial cavity through the hypoglossal canal and is medial to the internal jugular vein and internal carotid artery immediately outside the skull. As it descends, it passes outward between the internal jugular vein and internal carotid artery (Fig. 8.175). At this point it passes forward, hooking around the occipital artery, across the lateral surfaces of the internal and external carotid arteries and the lingual artery, and then continues deep to the posterior belly of the digastric and stylohyoid muscles. It passes over the surface of the hyoglossus muscle and disappears deep to the mylohyoid muscle. The hypoglossal nerve [XII], which supplies the tongue, does not give off any branches as it passes through the anterior triangle of the neck. |
Anatomy_Gray_2428 | Anatomy_Gray | The hypoglossal nerve [XII], which supplies the tongue, does not give off any branches as it passes through the anterior triangle of the neck. The transverse cervical nerve is a branch of the cervical plexus arising from the anterior rami of cervical nerves C2 and C3. It emerges from beneath the posterior border of the sternocleidomastoid muscle, near the middle of the muscle, and loops around the sternocleidomastoid to cross its anterior surface in a transverse direction (Fig. 8.176). It continues across the neck and provides cutaneous innervation to this area. The ansa cervicalis is a loop of nerve fibers from cervical nerves C1 to C3 that innervate the “strap muscles” in the anterior triangle of the neck (Fig. 8.177). It begins as branches from the cervical nerve C1 join the hypoglossal nerve [XII] soon after it leaves the skull. | Anatomy_Gray. The hypoglossal nerve [XII], which supplies the tongue, does not give off any branches as it passes through the anterior triangle of the neck. The transverse cervical nerve is a branch of the cervical plexus arising from the anterior rami of cervical nerves C2 and C3. It emerges from beneath the posterior border of the sternocleidomastoid muscle, near the middle of the muscle, and loops around the sternocleidomastoid to cross its anterior surface in a transverse direction (Fig. 8.176). It continues across the neck and provides cutaneous innervation to this area. The ansa cervicalis is a loop of nerve fibers from cervical nerves C1 to C3 that innervate the “strap muscles” in the anterior triangle of the neck (Fig. 8.177). It begins as branches from the cervical nerve C1 join the hypoglossal nerve [XII] soon after it leaves the skull. |
Anatomy_Gray_2429 | Anatomy_Gray | As the hypoglossal nerve [XII] completes its descent and begins to pass forward across the internal and external carotid arteries, some of the cervical nerve fibers leave it and descend between the internal jugular vein and the internal, and then common, carotid arteries. These nerve fibers are the superior root of the ansa cervicalis and innervate the superior belly of the omohyoid muscle, and the upper parts of the sternohyoid and sternothyroid muscles. Completing the loop is a direct branch from the cervical plexus containing nerve fibers from the second and third cervical nerves C2 and C3 (Fig. 8.177). This is the inferior root of the ansa cervicalis. It descends either medial or lateral to the internal jugular vein before turning medially to join the superior root. At this location, the ansa cervicalis gives off branches that innervate the inferior belly of the omohyoid, and the lower parts of the sternohyoid and sternothyroid muscles. Elements of the gastrointestinal | Anatomy_Gray. As the hypoglossal nerve [XII] completes its descent and begins to pass forward across the internal and external carotid arteries, some of the cervical nerve fibers leave it and descend between the internal jugular vein and the internal, and then common, carotid arteries. These nerve fibers are the superior root of the ansa cervicalis and innervate the superior belly of the omohyoid muscle, and the upper parts of the sternohyoid and sternothyroid muscles. Completing the loop is a direct branch from the cervical plexus containing nerve fibers from the second and third cervical nerves C2 and C3 (Fig. 8.177). This is the inferior root of the ansa cervicalis. It descends either medial or lateral to the internal jugular vein before turning medially to join the superior root. At this location, the ansa cervicalis gives off branches that innervate the inferior belly of the omohyoid, and the lower parts of the sternohyoid and sternothyroid muscles. Elements of the gastrointestinal |
Anatomy_Gray_2430 | Anatomy_Gray | Elements of the gastrointestinal The esophagus, trachea, pharynx, and larynx lie in the neck and are related to the anterior triangles. The esophagus is part of the gastrointestinal system and has only a short course in the lower neck. It begins at vertebral level CVI, where it is continuous with the pharynx above and courses inferiorly to pass through the thoracic inlet. It lies directly anterior to the vertebral column (Fig. 8.178B). The trachea is part of the lower airway and, like the esophagus, begins at vertebral level CVI, where it is continuous with the larynx above (Fig. 8.178B). The trachea lies directly anterior to the esophagus and passes inferiorly in the midline to enter the thorax. The pharynx is a common pathway for air and food, and the head with similar compartments in the lower neck (see pp. 1029–1041). The larynx is the upper end of the lower airway. It is continuous with the trachea below and the pharynx posterosuperiorly (see pp. 1041–1058). | Anatomy_Gray. Elements of the gastrointestinal The esophagus, trachea, pharynx, and larynx lie in the neck and are related to the anterior triangles. The esophagus is part of the gastrointestinal system and has only a short course in the lower neck. It begins at vertebral level CVI, where it is continuous with the pharynx above and courses inferiorly to pass through the thoracic inlet. It lies directly anterior to the vertebral column (Fig. 8.178B). The trachea is part of the lower airway and, like the esophagus, begins at vertebral level CVI, where it is continuous with the larynx above (Fig. 8.178B). The trachea lies directly anterior to the esophagus and passes inferiorly in the midline to enter the thorax. The pharynx is a common pathway for air and food, and the head with similar compartments in the lower neck (see pp. 1029–1041). The larynx is the upper end of the lower airway. It is continuous with the trachea below and the pharynx posterosuperiorly (see pp. 1041–1058). |
Anatomy_Gray_2431 | Anatomy_Gray | The larynx is the upper end of the lower airway. It is continuous with the trachea below and the pharynx posterosuperiorly (see pp. 1041–1058). The thyroid and parathyroid glands are endocrine glands positioned anteriorly in the neck. Both glands begin as pharyngeal outgrowths that migrate caudally to their final positions as development continues. The thyroid gland is a large, unpaired gland, while the parathyroid glands, usually four in number, are small and are on the posterior surface of the thyroid gland. The thyroid gland is anterior in the neck below and lateral to the thyroid cartilage (Fig. 8.178). It consists of two lateral lobes (which cover the anterolateral surfaces of the trachea, the cricoid cartilage, and the lower part of the thyroid cartilage) with an isthmus that connects the lateral lobes and crosses the anterior surfaces of the second and third tracheal cartilages. | Anatomy_Gray. The larynx is the upper end of the lower airway. It is continuous with the trachea below and the pharynx posterosuperiorly (see pp. 1041–1058). The thyroid and parathyroid glands are endocrine glands positioned anteriorly in the neck. Both glands begin as pharyngeal outgrowths that migrate caudally to their final positions as development continues. The thyroid gland is a large, unpaired gland, while the parathyroid glands, usually four in number, are small and are on the posterior surface of the thyroid gland. The thyroid gland is anterior in the neck below and lateral to the thyroid cartilage (Fig. 8.178). It consists of two lateral lobes (which cover the anterolateral surfaces of the trachea, the cricoid cartilage, and the lower part of the thyroid cartilage) with an isthmus that connects the lateral lobes and crosses the anterior surfaces of the second and third tracheal cartilages. |
Anatomy_Gray_2432 | Anatomy_Gray | Lying deep to the sternohyoid, sternothyroid, and omohyoid muscles, the thyroid gland is in the visceral compartment of the neck. This compartment also includes the pharynx, trachea, and esophagus and is surrounded by the pretracheal layers of fascia. The thyroid gland arises as a median outgrowth from the floor of the pharynx near the base of the tongue. The foramen cecum of the tongue indicates the site of origin and the thyroglossal duct marks the path of migration of the thyroid gland to its final adult location. The thyroglossal duct usually disappears early in development, but remnants may persist as a cyst or as a connection to the foramen cecum (i.e., a fistula). There may also be functional thyroid gland: associated with the tongue (a lingual thyroid), anywhere along the path of migration of the thyroid gland, or extending upward from the gland along the path of the thyroglossal duct (a pyramidal lobe). Two major arteries supply the thyroid gland. | Anatomy_Gray. Lying deep to the sternohyoid, sternothyroid, and omohyoid muscles, the thyroid gland is in the visceral compartment of the neck. This compartment also includes the pharynx, trachea, and esophagus and is surrounded by the pretracheal layers of fascia. The thyroid gland arises as a median outgrowth from the floor of the pharynx near the base of the tongue. The foramen cecum of the tongue indicates the site of origin and the thyroglossal duct marks the path of migration of the thyroid gland to its final adult location. The thyroglossal duct usually disappears early in development, but remnants may persist as a cyst or as a connection to the foramen cecum (i.e., a fistula). There may also be functional thyroid gland: associated with the tongue (a lingual thyroid), anywhere along the path of migration of the thyroid gland, or extending upward from the gland along the path of the thyroglossal duct (a pyramidal lobe). Two major arteries supply the thyroid gland. |
Anatomy_Gray_2433 | Anatomy_Gray | Two major arteries supply the thyroid gland. Superior thyroid artery. The superior thyroid artery is the first branch of the external carotid artery (Fig. 8.179). It descends, passing along the lateral margin of the thyrohyoid muscle, to reach the superior pole of the lateral lobe of the gland where it divides into anterior and posterior glandular branches: The anterior glandular branch passes along the superior border of the thyroid gland and anastomoses with its twin from the opposite side across the isthmus (Fig. 8.179). The posterior glandular branch passes to the posterior side of the gland and may anastomose with the inferior thyroid artery (Fig. 8.180). | Anatomy_Gray. Two major arteries supply the thyroid gland. Superior thyroid artery. The superior thyroid artery is the first branch of the external carotid artery (Fig. 8.179). It descends, passing along the lateral margin of the thyrohyoid muscle, to reach the superior pole of the lateral lobe of the gland where it divides into anterior and posterior glandular branches: The anterior glandular branch passes along the superior border of the thyroid gland and anastomoses with its twin from the opposite side across the isthmus (Fig. 8.179). The posterior glandular branch passes to the posterior side of the gland and may anastomose with the inferior thyroid artery (Fig. 8.180). |
Anatomy_Gray_2434 | Anatomy_Gray | The posterior glandular branch passes to the posterior side of the gland and may anastomose with the inferior thyroid artery (Fig. 8.180). Inferior thyroid artery. The inferior thyroid artery is a branch of the thyrocervical trunk, which arises from the first part of the subclavian artery (Figs. 8.179 and 8.180). It ascends along the medial edge of the anterior scalene muscle, passes posteriorly to the carotid sheath, and reaches the inferior pole of the lateral lobe of the thyroid gland. At the thyroid gland the inferior thyroid artery divides into an: inferior branch, which supplies the lower part of the thyroid gland and anastomoses with the posterior branch of the superior thyroid artery, and an ascending branch, which supplies the parathyroid glands. Occasionally, a small thyroid ima artery arises from the brachiocephalic trunk or the arch of the aorta and ascends on the anterior surface of the trachea to supply the thyroid gland. | Anatomy_Gray. The posterior glandular branch passes to the posterior side of the gland and may anastomose with the inferior thyroid artery (Fig. 8.180). Inferior thyroid artery. The inferior thyroid artery is a branch of the thyrocervical trunk, which arises from the first part of the subclavian artery (Figs. 8.179 and 8.180). It ascends along the medial edge of the anterior scalene muscle, passes posteriorly to the carotid sheath, and reaches the inferior pole of the lateral lobe of the thyroid gland. At the thyroid gland the inferior thyroid artery divides into an: inferior branch, which supplies the lower part of the thyroid gland and anastomoses with the posterior branch of the superior thyroid artery, and an ascending branch, which supplies the parathyroid glands. Occasionally, a small thyroid ima artery arises from the brachiocephalic trunk or the arch of the aorta and ascends on the anterior surface of the trachea to supply the thyroid gland. |
Anatomy_Gray_2435 | Anatomy_Gray | Occasionally, a small thyroid ima artery arises from the brachiocephalic trunk or the arch of the aorta and ascends on the anterior surface of the trachea to supply the thyroid gland. Three veins drain the thyroid gland (Fig. 8.179): The superior thyroid vein primarily drains the area supplied by the superior thyroid artery. The middle and inferior thyroid veins drain the rest of the thyroid gland. The superior and middle thyroid veins drain into the internal jugular vein, and the inferior thyroid veins empty into the right and left brachiocephalic veins, respectively. Lymphatic drainage of the thyroid gland is to nodes beside the trachea (paratracheal nodes) and to deep cervical nodes inferior to the omohyoid muscle along the internal jugular vein. | Anatomy_Gray. Occasionally, a small thyroid ima artery arises from the brachiocephalic trunk or the arch of the aorta and ascends on the anterior surface of the trachea to supply the thyroid gland. Three veins drain the thyroid gland (Fig. 8.179): The superior thyroid vein primarily drains the area supplied by the superior thyroid artery. The middle and inferior thyroid veins drain the rest of the thyroid gland. The superior and middle thyroid veins drain into the internal jugular vein, and the inferior thyroid veins empty into the right and left brachiocephalic veins, respectively. Lymphatic drainage of the thyroid gland is to nodes beside the trachea (paratracheal nodes) and to deep cervical nodes inferior to the omohyoid muscle along the internal jugular vein. |
Anatomy_Gray_2436 | Anatomy_Gray | Lymphatic drainage of the thyroid gland is to nodes beside the trachea (paratracheal nodes) and to deep cervical nodes inferior to the omohyoid muscle along the internal jugular vein. The thyroid gland is closely related to the recurrent laryngeal nerves. After branching from the vagus nerve [X] and looping around the subclavian artery on the right and the arch of the aorta on the left, the recurrent laryngeal nerves ascend in a groove between the trachea and esophagus (Fig. 8.180). They pass deep to the posteromedial surface of the lateral lobes of the thyroid gland and enter the larynx by passing deep to the lower margin of the inferior constrictor of the pharynx. | Anatomy_Gray. Lymphatic drainage of the thyroid gland is to nodes beside the trachea (paratracheal nodes) and to deep cervical nodes inferior to the omohyoid muscle along the internal jugular vein. The thyroid gland is closely related to the recurrent laryngeal nerves. After branching from the vagus nerve [X] and looping around the subclavian artery on the right and the arch of the aorta on the left, the recurrent laryngeal nerves ascend in a groove between the trachea and esophagus (Fig. 8.180). They pass deep to the posteromedial surface of the lateral lobes of the thyroid gland and enter the larynx by passing deep to the lower margin of the inferior constrictor of the pharynx. |
Anatomy_Gray_2437 | Anatomy_Gray | Together with branches of the inferior thyroid arteries, the recurrent laryngeal nerves are clearly related to, and may pass through ligaments, one on each side, that bind the thyroid gland to the trachea and to the cricoid cartilage of the larynx. These relationships need to be considered when surgically removing or manipulating the thyroid gland. The parathyroid glands are two pairs of small, ovoid, yellowish structures on the deep surface of the lateral lobes of the thyroid gland. They are designated as the superior and inferior parathyroid glands (Fig. 8.180). However, their position is quite variable and they may be anywhere from the carotid bifurcation superiorly to the mediastinum inferiorly. Derived from the third (the inferior parathyroid glands) and fourth (the superior parathyroid glands) pharyngeal pouches, these paired structures migrate to their final adult positions and are named accordingly. | Anatomy_Gray. Together with branches of the inferior thyroid arteries, the recurrent laryngeal nerves are clearly related to, and may pass through ligaments, one on each side, that bind the thyroid gland to the trachea and to the cricoid cartilage of the larynx. These relationships need to be considered when surgically removing or manipulating the thyroid gland. The parathyroid glands are two pairs of small, ovoid, yellowish structures on the deep surface of the lateral lobes of the thyroid gland. They are designated as the superior and inferior parathyroid glands (Fig. 8.180). However, their position is quite variable and they may be anywhere from the carotid bifurcation superiorly to the mediastinum inferiorly. Derived from the third (the inferior parathyroid glands) and fourth (the superior parathyroid glands) pharyngeal pouches, these paired structures migrate to their final adult positions and are named accordingly. |
Anatomy_Gray_2438 | Anatomy_Gray | The arteries supplying the parathyroid glands are the inferior thyroid arteries, and venous and lymphatic drainage follows that described for the thyroid gland. Location of structures in different regions of the anterior triangle of the neck The regional location of major structures in the anterior triangle of the neck is summarized in Table 8.14. Structures can be identified as being within a specific subdivision, passing into a specific subdivision from outside the area, originating in one subdivision and passing to another subdivision, or passing through several subdivisions while traversing the region. Posterior triangle of the neck | Anatomy_Gray. The arteries supplying the parathyroid glands are the inferior thyroid arteries, and venous and lymphatic drainage follows that described for the thyroid gland. Location of structures in different regions of the anterior triangle of the neck The regional location of major structures in the anterior triangle of the neck is summarized in Table 8.14. Structures can be identified as being within a specific subdivision, passing into a specific subdivision from outside the area, originating in one subdivision and passing to another subdivision, or passing through several subdivisions while traversing the region. Posterior triangle of the neck |
Anatomy_Gray_2439 | Anatomy_Gray | Posterior triangle of the neck The posterior triangle of the neck is on the lateral aspect of the neck in direct continuity with the upper limb (Fig. 8.183). It is bordered: anteriorly by the posterior edge of the sternocleidomastoid muscle, posteriorly by the anterior edge of the trapezius muscle, basally by the middle one-third of the clavicle, and apically by the occipital bone just posterior to the mastoid process where the attachments of the trapezius and sternocleidomastoid come together. The roof of the posterior triangle consists of an investing layer of cervical fascia that surrounds the sternocleidomastoid and trapezius muscles as it passes through the region. The muscular floor of the posterior triangle is covered by the prevertebral layer of cervical fascia; and from superior to inferior consists of the splenius capitis, levator scapulae, and the posterior, middle, and anterior scalene muscles. | Anatomy_Gray. Posterior triangle of the neck The posterior triangle of the neck is on the lateral aspect of the neck in direct continuity with the upper limb (Fig. 8.183). It is bordered: anteriorly by the posterior edge of the sternocleidomastoid muscle, posteriorly by the anterior edge of the trapezius muscle, basally by the middle one-third of the clavicle, and apically by the occipital bone just posterior to the mastoid process where the attachments of the trapezius and sternocleidomastoid come together. The roof of the posterior triangle consists of an investing layer of cervical fascia that surrounds the sternocleidomastoid and trapezius muscles as it passes through the region. The muscular floor of the posterior triangle is covered by the prevertebral layer of cervical fascia; and from superior to inferior consists of the splenius capitis, levator scapulae, and the posterior, middle, and anterior scalene muscles. |
Anatomy_Gray_2440 | Anatomy_Gray | Numerous muscles participate in forming the borders and floor of the posterior triangle of the neck (Table 8.15). In addition, the omohyoid muscle passes across the inferior part of the posterior triangle before disappearing under the sternocleidomastoid muscle and emerging in the anterior triangle (Fig. 8.184). It is enclosed in the investing layer of cervical fascia and crosses the posterior triangle from lateral to medial as it continues in a superior direction. It originates on the superior border of the scapula, just medial to the scapular notch and eventually inserts into the inferior border of the body of the hyoid bone. It has two bellies connected by a tendon, which is anchored by a fascial sling to the clavicle: The superior belly is in the anterior triangle. The inferior belly crosses the posterior triangle, subdividing it into a small, omoclavicular or subclavian triangle inferiorly and a much larger occipital triangle superiorly. | Anatomy_Gray. Numerous muscles participate in forming the borders and floor of the posterior triangle of the neck (Table 8.15). In addition, the omohyoid muscle passes across the inferior part of the posterior triangle before disappearing under the sternocleidomastoid muscle and emerging in the anterior triangle (Fig. 8.184). It is enclosed in the investing layer of cervical fascia and crosses the posterior triangle from lateral to medial as it continues in a superior direction. It originates on the superior border of the scapula, just medial to the scapular notch and eventually inserts into the inferior border of the body of the hyoid bone. It has two bellies connected by a tendon, which is anchored by a fascial sling to the clavicle: The superior belly is in the anterior triangle. The inferior belly crosses the posterior triangle, subdividing it into a small, omoclavicular or subclavian triangle inferiorly and a much larger occipital triangle superiorly. |
Anatomy_Gray_2441 | Anatomy_Gray | The inferior belly crosses the posterior triangle, subdividing it into a small, omoclavicular or subclavian triangle inferiorly and a much larger occipital triangle superiorly. The omohyoid is innervated by branches of the ansa cervicalis (anterior rami from C1 to C3) and it depresses the hyoid bone. One of the most superficial structures passing through the posterior triangle of the neck is the external jugular vein (Fig. 8.185). This large vein forms near the angle of the mandible, when the posterior branch of the retromandibular and posterior auricular veins join, and descends through the neck in the superficial fascia. After crossing the sternocleidomastoid muscle, the external jugular vein enters the posterior triangle and continues its vertical descent. In the lower part of the posterior triangle, the external jugular vein pierces the investing layer of cervical fascia and ends in the subclavian vein. | Anatomy_Gray. The inferior belly crosses the posterior triangle, subdividing it into a small, omoclavicular or subclavian triangle inferiorly and a much larger occipital triangle superiorly. The omohyoid is innervated by branches of the ansa cervicalis (anterior rami from C1 to C3) and it depresses the hyoid bone. One of the most superficial structures passing through the posterior triangle of the neck is the external jugular vein (Fig. 8.185). This large vein forms near the angle of the mandible, when the posterior branch of the retromandibular and posterior auricular veins join, and descends through the neck in the superficial fascia. After crossing the sternocleidomastoid muscle, the external jugular vein enters the posterior triangle and continues its vertical descent. In the lower part of the posterior triangle, the external jugular vein pierces the investing layer of cervical fascia and ends in the subclavian vein. |
Anatomy_Gray_2442 | Anatomy_Gray | In the lower part of the posterior triangle, the external jugular vein pierces the investing layer of cervical fascia and ends in the subclavian vein. Tributaries to the external jugular vein while it traverses the posterior triangle of the neck include the transverse cervical, suprascapular, and anterior jugular veins. Several arteries are found within the boundaries of the posterior triangle of the neck. The largest is the third part of the subclavian artery as it crosses the base of the posterior triangle (Fig. 8.186). The first part of the subclavian artery ascends to the medial border of the anterior scalene muscle from either the brachiocephalic trunk on the right side or directly from the arch of the aorta on the left side. It has numerous branches. The second part of the subclavian artery passes laterally between the anterior and middle scalene muscles, and one branch may arise from it. | Anatomy_Gray. In the lower part of the posterior triangle, the external jugular vein pierces the investing layer of cervical fascia and ends in the subclavian vein. Tributaries to the external jugular vein while it traverses the posterior triangle of the neck include the transverse cervical, suprascapular, and anterior jugular veins. Several arteries are found within the boundaries of the posterior triangle of the neck. The largest is the third part of the subclavian artery as it crosses the base of the posterior triangle (Fig. 8.186). The first part of the subclavian artery ascends to the medial border of the anterior scalene muscle from either the brachiocephalic trunk on the right side or directly from the arch of the aorta on the left side. It has numerous branches. The second part of the subclavian artery passes laterally between the anterior and middle scalene muscles, and one branch may arise from it. |
Anatomy_Gray_2443 | Anatomy_Gray | The second part of the subclavian artery passes laterally between the anterior and middle scalene muscles, and one branch may arise from it. The third part of the subclavian artery emerges from between the anterior and middle scalene muscles to cross the base of the posterior triangle (Fig. 8.186). It extends from the lateral border of the anterior scalene muscle to the lateral border of rib I where it becomes the axillary artery and continues into the upper limb. A single branch (the dorsal scapular artery) may arise from the third part of the subclavian artery. This branch passes posterolaterally to reach the superior angle of the scapula where it descends along the medial border of the scapula posterior to the rhomboid muscles. | Anatomy_Gray. The second part of the subclavian artery passes laterally between the anterior and middle scalene muscles, and one branch may arise from it. The third part of the subclavian artery emerges from between the anterior and middle scalene muscles to cross the base of the posterior triangle (Fig. 8.186). It extends from the lateral border of the anterior scalene muscle to the lateral border of rib I where it becomes the axillary artery and continues into the upper limb. A single branch (the dorsal scapular artery) may arise from the third part of the subclavian artery. This branch passes posterolaterally to reach the superior angle of the scapula where it descends along the medial border of the scapula posterior to the rhomboid muscles. |
Anatomy_Gray_2444 | Anatomy_Gray | Two other small arteries also cross the base of the posterior triangle. These are the transverse cervical and the suprascapular arteries (Fig. 8.186). They are both branches of the thyrocervical trunk, which arises from the first part of the subclavian artery. After branching from the thyrocervical trunk, the transverse cervical artery passes laterally and slightly posteriorly across the base of the posterior triangle anterior to the anterior scalene muscle and the brachial plexus. Reaching the deep surface of the trapezius muscle, it divides into superficial and deep branches: The superficial branch continues on the deep surface of the trapezius muscle. The deep branch continues on the deep surface of the rhomboid muscles near the medial border of the scapula. | Anatomy_Gray. Two other small arteries also cross the base of the posterior triangle. These are the transverse cervical and the suprascapular arteries (Fig. 8.186). They are both branches of the thyrocervical trunk, which arises from the first part of the subclavian artery. After branching from the thyrocervical trunk, the transverse cervical artery passes laterally and slightly posteriorly across the base of the posterior triangle anterior to the anterior scalene muscle and the brachial plexus. Reaching the deep surface of the trapezius muscle, it divides into superficial and deep branches: The superficial branch continues on the deep surface of the trapezius muscle. The deep branch continues on the deep surface of the rhomboid muscles near the medial border of the scapula. |
Anatomy_Gray_2445 | Anatomy_Gray | The superficial branch continues on the deep surface of the trapezius muscle. The deep branch continues on the deep surface of the rhomboid muscles near the medial border of the scapula. The suprascapular artery, also a branch of the thyrocervical trunk, passes laterally, in a slightly downward direction across the lowest part of the posterior triangle, and ends up posterior to the clavicle (Fig. 8.186). Approaching the scapula, it passes over the superior transverse scapular ligament and distributes branches to muscles on the posterior surface of the scapula. Veins accompany all the arteries described previously. | Anatomy_Gray. The superficial branch continues on the deep surface of the trapezius muscle. The deep branch continues on the deep surface of the rhomboid muscles near the medial border of the scapula. The suprascapular artery, also a branch of the thyrocervical trunk, passes laterally, in a slightly downward direction across the lowest part of the posterior triangle, and ends up posterior to the clavicle (Fig. 8.186). Approaching the scapula, it passes over the superior transverse scapular ligament and distributes branches to muscles on the posterior surface of the scapula. Veins accompany all the arteries described previously. |
Anatomy_Gray_2446 | Anatomy_Gray | Veins accompany all the arteries described previously. The subclavian vein is a continuation of the axillary vein and begins at the lateral border of rib I. As it crosses the base of the posterior triangle, the external jugular, and, possibly, the suprascapular and transverse cervical veins enter it (Fig. 8.185). It ends by joining with the internal jugular vein to form the brachiocephalic vein near the sternoclavicular joint. In the posterior triangle it is anterior to, and slightly lower than, the subclavian artery and passes anterior to the anterior scalene muscle. Transverse cervical and suprascapular veins travel with each of the similarly named arteries. These veins become tributaries to either the external jugular vein or the initial part of the subclavian vein. | Anatomy_Gray. Veins accompany all the arteries described previously. The subclavian vein is a continuation of the axillary vein and begins at the lateral border of rib I. As it crosses the base of the posterior triangle, the external jugular, and, possibly, the suprascapular and transverse cervical veins enter it (Fig. 8.185). It ends by joining with the internal jugular vein to form the brachiocephalic vein near the sternoclavicular joint. In the posterior triangle it is anterior to, and slightly lower than, the subclavian artery and passes anterior to the anterior scalene muscle. Transverse cervical and suprascapular veins travel with each of the similarly named arteries. These veins become tributaries to either the external jugular vein or the initial part of the subclavian vein. |
Anatomy_Gray_2447 | Anatomy_Gray | A variety of nerves pass through or are within the posterior triangle. These include the accessory nerve [XI], branches of the cervical plexus, components forming the brachial plexus, and branches of the brachial plexus. | Anatomy_Gray. A variety of nerves pass through or are within the posterior triangle. These include the accessory nerve [XI], branches of the cervical plexus, components forming the brachial plexus, and branches of the brachial plexus. |
Anatomy_Gray_2448 | Anatomy_Gray | The accessory nerve [XI] exits the cranial cavity through the jugular foramen. It descends through the neck in a posterior direction, to reach the anterior border of the sternocleidomastoid muscle. Passing either deep to or through and innervating the sternocleidomastoid muscle, the accessory nerve [XI] continues to descend and enters the posterior triangle (Fig. 8.187). It crosses the posterior triangle, still in an obliquely downward direction, within the investing layer of cervical fascia as this fascia crosses between the sternocleidomastoid and trapezius muscles. When the accessory nerve [XI] reaches the anterior border of the trapezius muscle, it continues on the deep surface of the trapezius and innervates it. The superficial location of the accessory nerve as it crosses the posterior triangle makes it susceptible to injury. The cervical plexus is formed by the anterior rami of cervical nerves C1 to C4 (Fig. 8.188). | Anatomy_Gray. The accessory nerve [XI] exits the cranial cavity through the jugular foramen. It descends through the neck in a posterior direction, to reach the anterior border of the sternocleidomastoid muscle. Passing either deep to or through and innervating the sternocleidomastoid muscle, the accessory nerve [XI] continues to descend and enters the posterior triangle (Fig. 8.187). It crosses the posterior triangle, still in an obliquely downward direction, within the investing layer of cervical fascia as this fascia crosses between the sternocleidomastoid and trapezius muscles. When the accessory nerve [XI] reaches the anterior border of the trapezius muscle, it continues on the deep surface of the trapezius and innervates it. The superficial location of the accessory nerve as it crosses the posterior triangle makes it susceptible to injury. The cervical plexus is formed by the anterior rami of cervical nerves C1 to C4 (Fig. 8.188). |
Anatomy_Gray_2449 | Anatomy_Gray | The cervical plexus is formed by the anterior rami of cervical nerves C1 to C4 (Fig. 8.188). The cervical plexus forms in the substance of the muscles making up the floor of the posterior triangle within the prevertebral layer of cervical fascia, and consists of: muscular (or deep) branches, and cutaneous (or superficial) branches. The cutaneous branches are visible in the posterior triangle emerging from beneath the posterior border of the sternocleidomastoid muscle (Fig. 8.187). | Anatomy_Gray. The cervical plexus is formed by the anterior rami of cervical nerves C1 to C4 (Fig. 8.188). The cervical plexus forms in the substance of the muscles making up the floor of the posterior triangle within the prevertebral layer of cervical fascia, and consists of: muscular (or deep) branches, and cutaneous (or superficial) branches. The cutaneous branches are visible in the posterior triangle emerging from beneath the posterior border of the sternocleidomastoid muscle (Fig. 8.187). |
Anatomy_Gray_2450 | Anatomy_Gray | The cutaneous branches are visible in the posterior triangle emerging from beneath the posterior border of the sternocleidomastoid muscle (Fig. 8.187). Muscular (deep) branches of the cervical plexus distribute to several groups of muscles. A major branch is the phrenic nerve, which supplies the diaphragm with both sensory and motor innervation (Fig. 8.188). It arises from the anterior rami of cervical nerves C3 to C5. Hooking around the upper lateral border of the anterior scalene muscle, the nerve continues inferiorly across the anterior surface of the anterior scalene within the prevertebral fascia to enter the thorax (Fig. 8.189). As the nerve descends in the neck, it is “pinned” to the anterior scalene muscle by the transverse cervical and suprascapular arteries. | Anatomy_Gray. The cutaneous branches are visible in the posterior triangle emerging from beneath the posterior border of the sternocleidomastoid muscle (Fig. 8.187). Muscular (deep) branches of the cervical plexus distribute to several groups of muscles. A major branch is the phrenic nerve, which supplies the diaphragm with both sensory and motor innervation (Fig. 8.188). It arises from the anterior rami of cervical nerves C3 to C5. Hooking around the upper lateral border of the anterior scalene muscle, the nerve continues inferiorly across the anterior surface of the anterior scalene within the prevertebral fascia to enter the thorax (Fig. 8.189). As the nerve descends in the neck, it is “pinned” to the anterior scalene muscle by the transverse cervical and suprascapular arteries. |
Anatomy_Gray_2451 | Anatomy_Gray | Several muscular branches of the cervical plexus supply prevertebral and lateral vertebral muscles, including the rectus capitis anterior, rectus capitis lateralis, longus colli, and longus capitis (Fig. 8.189 and Table 8.16). The cervical plexus also contributes to the formation of the superior and inferior roots of the ansa cervicalis (Fig. 8.188). This loop of nerves receives contributions from the anterior rami of the cervical nerves C1 to C3 and innervates the infrahyoid muscles. Cutaneous (superficial) branches of the cervical plexus are visible in the posterior triangle as they pass outward from the posterior border of the sternocleidomastoid muscle (Figs. 8.187 and 8.188): The lesser occipital nerve consists of contributions from cervical nerve C2 (Fig. 8.188), ascends along the posterior border of the sternocleidomastoid muscle, and distributes to the skin of the neck and scalp posterior to the ear. | Anatomy_Gray. Several muscular branches of the cervical plexus supply prevertebral and lateral vertebral muscles, including the rectus capitis anterior, rectus capitis lateralis, longus colli, and longus capitis (Fig. 8.189 and Table 8.16). The cervical plexus also contributes to the formation of the superior and inferior roots of the ansa cervicalis (Fig. 8.188). This loop of nerves receives contributions from the anterior rami of the cervical nerves C1 to C3 and innervates the infrahyoid muscles. Cutaneous (superficial) branches of the cervical plexus are visible in the posterior triangle as they pass outward from the posterior border of the sternocleidomastoid muscle (Figs. 8.187 and 8.188): The lesser occipital nerve consists of contributions from cervical nerve C2 (Fig. 8.188), ascends along the posterior border of the sternocleidomastoid muscle, and distributes to the skin of the neck and scalp posterior to the ear. |
Anatomy_Gray_2452 | Anatomy_Gray | The great auricular nerve consists of branches from cervical nerves C2 and C3, emerges from the posterior border of the sternocleidomastoid muscle, and ascends across the muscle to the base of the ear, supplying the skin of the parotid region, the ear, and the mastoid area. The transverse cervical nerve consists of branches from the cervical nerves C2 and C3, passes around the midpart of the sternocleidomastoid muscle, and continues horizontally across the muscle to supply the lateral and anterior parts of the neck. The supraclavicular nerves are a group of cutaneous nerves from cervical nerves C3 and C4 that, after emerging from beneath the posterior border of the sternocleidomastoid muscle, descend and supply the skin over the clavicle and shoulder as far inferiorly as rib II. | Anatomy_Gray. The great auricular nerve consists of branches from cervical nerves C2 and C3, emerges from the posterior border of the sternocleidomastoid muscle, and ascends across the muscle to the base of the ear, supplying the skin of the parotid region, the ear, and the mastoid area. The transverse cervical nerve consists of branches from the cervical nerves C2 and C3, passes around the midpart of the sternocleidomastoid muscle, and continues horizontally across the muscle to supply the lateral and anterior parts of the neck. The supraclavicular nerves are a group of cutaneous nerves from cervical nerves C3 and C4 that, after emerging from beneath the posterior border of the sternocleidomastoid muscle, descend and supply the skin over the clavicle and shoulder as far inferiorly as rib II. |
Anatomy_Gray_2453 | Anatomy_Gray | The brachial plexus forms from the anterior rami of cervical nerves C5 to C8 and thoracic nerve T1. The contributions of each of these nerves, which are between the anterior and middle scalene muscles, are the roots of the brachial plexus. As the roots emerge from between these muscles, they form the next component of the brachial plexus (the trunks) as follows: the anterior rami of C5 and C6 form the upper trunk, the anterior ramus of C7 forms the middle trunk, the anterior rami of C8 and T1 form the lower trunk. The trunks cross the base of the posterior triangle (see Fig. 8.186). Several branches of the brachial plexus may be visible in the posterior triangle (see Fig. 7.54 on pg. 730). These include the: dorsal scapular nerve to the rhomboid muscles, long thoracic nerve to the serratus anterior muscle, nerve to the subclavius muscle, and suprascapular nerve to the supraspinatus and infraspinatus muscles. Root of the neck | Anatomy_Gray. The brachial plexus forms from the anterior rami of cervical nerves C5 to C8 and thoracic nerve T1. The contributions of each of these nerves, which are between the anterior and middle scalene muscles, are the roots of the brachial plexus. As the roots emerge from between these muscles, they form the next component of the brachial plexus (the trunks) as follows: the anterior rami of C5 and C6 form the upper trunk, the anterior ramus of C7 forms the middle trunk, the anterior rami of C8 and T1 form the lower trunk. The trunks cross the base of the posterior triangle (see Fig. 8.186). Several branches of the brachial plexus may be visible in the posterior triangle (see Fig. 7.54 on pg. 730). These include the: dorsal scapular nerve to the rhomboid muscles, long thoracic nerve to the serratus anterior muscle, nerve to the subclavius muscle, and suprascapular nerve to the supraspinatus and infraspinatus muscles. Root of the neck |
Anatomy_Gray_2454 | Anatomy_Gray | Root of the neck The root of the neck (Fig. 8.190) is the area immediately superior to the superior thoracic aperture and axillary inlets. It is bounded by: the top of the manubrium of the sternum and superior margin of the clavicle anteriorly, and the top of the thoracic vertebra TI and the superior margin of the scapula to the coracoid process posteriorly. It contains structures passing between the neck, thorax, and upper limb. There is also an extension of the thoracic cavity projecting into the root of the neck (Fig. 8.190). This consists of an upward projection of the pleural cavity, on both sides, and includes the cervical part of the parietal pleura (cupula), and the apical part of the superior lobe of each lung. Anteriorly, the pleural cavity extends above the top of the manubrium of the sternum and superior border of rib I, while posteriorly, due to the downward slope of the superior thoracic aperture, the pleural cavity remains below the top of vertebra TI. | Anatomy_Gray. Root of the neck The root of the neck (Fig. 8.190) is the area immediately superior to the superior thoracic aperture and axillary inlets. It is bounded by: the top of the manubrium of the sternum and superior margin of the clavicle anteriorly, and the top of the thoracic vertebra TI and the superior margin of the scapula to the coracoid process posteriorly. It contains structures passing between the neck, thorax, and upper limb. There is also an extension of the thoracic cavity projecting into the root of the neck (Fig. 8.190). This consists of an upward projection of the pleural cavity, on both sides, and includes the cervical part of the parietal pleura (cupula), and the apical part of the superior lobe of each lung. Anteriorly, the pleural cavity extends above the top of the manubrium of the sternum and superior border of rib I, while posteriorly, due to the downward slope of the superior thoracic aperture, the pleural cavity remains below the top of vertebra TI. |
Anatomy_Gray_2455 | Anatomy_Gray | The subclavian arteries on both sides arch upward out of the thorax to enter the root of the neck (Fig. 8.191). The right subclavian artery begins posterior to the sternoclavicular joint as one of two terminal branches of the brachiocephalic trunk. It arches superiorly and laterally to pass anterior to the extension of the pleural cavity in the root of the neck and posterior to the anterior scalene muscle. Continuing laterally across rib I, it becomes the axillary artery as it crosses its lateral border. The left subclavian artery begins lower in the thorax than the right subclavian artery as a direct branch of the arch of the aorta. Lying posterior to the left common carotid artery and lateral to the trachea, it ascends and arches laterally, passing anterior to the extension of the pleural cavity and posterior to the anterior scalene muscle. It continues laterally over rib I, and becomes the axillary artery as it crosses the lateral border of rib I. | Anatomy_Gray. The subclavian arteries on both sides arch upward out of the thorax to enter the root of the neck (Fig. 8.191). The right subclavian artery begins posterior to the sternoclavicular joint as one of two terminal branches of the brachiocephalic trunk. It arches superiorly and laterally to pass anterior to the extension of the pleural cavity in the root of the neck and posterior to the anterior scalene muscle. Continuing laterally across rib I, it becomes the axillary artery as it crosses its lateral border. The left subclavian artery begins lower in the thorax than the right subclavian artery as a direct branch of the arch of the aorta. Lying posterior to the left common carotid artery and lateral to the trachea, it ascends and arches laterally, passing anterior to the extension of the pleural cavity and posterior to the anterior scalene muscle. It continues laterally over rib I, and becomes the axillary artery as it crosses the lateral border of rib I. |
Anatomy_Gray_2456 | Anatomy_Gray | Both subclavian arteries are divided into three parts by the anterior scalene muscle (Fig. 8.191): The first part extends from the origin of the artery to the anterior scalene muscle. The second part is the part of the artery posterior to the anterior scalene muscle. The third part is the part lateral to the anterior scalene muscle before the artery reaches the lateral border of rib I. All branches from the right and left subclavian arteries arise from the first part of the artery, except in the case of one branch (the costocervical trunk) on the right side (Fig. 8.191). The branches include the vertebral artery, the thyrocervical trunk, the internal thoracic artery, and the costocervical trunk. | Anatomy_Gray. Both subclavian arteries are divided into three parts by the anterior scalene muscle (Fig. 8.191): The first part extends from the origin of the artery to the anterior scalene muscle. The second part is the part of the artery posterior to the anterior scalene muscle. The third part is the part lateral to the anterior scalene muscle before the artery reaches the lateral border of rib I. All branches from the right and left subclavian arteries arise from the first part of the artery, except in the case of one branch (the costocervical trunk) on the right side (Fig. 8.191). The branches include the vertebral artery, the thyrocervical trunk, the internal thoracic artery, and the costocervical trunk. |
Anatomy_Gray_2457 | Anatomy_Gray | The vertebral artery is the first branch of the subclavian artery as it enters the root of the neck (Fig. 8.191). A large branch, arising from the first part of the subclavian artery medial to the anterior scalene muscle, it ascends and enters the foramen in the transverse process of vertebra CVI. Continuing to pass superiorly, the vertebral artery passes through the foramina of vertebrae CV to CI. At the superior border of vertebra CI, the artery turns medially and crosses the posterior arch of vertebra CI. From here it passes through the foramen magnum to enter the posterior cranial fossa. The second branch of the subclavian artery is the thyrocervical trunk (Fig. 8.191). It arises from the first part of the subclavian artery medial to the anterior scalene muscle, and divides into three branches—the inferior thyroid, the transverse cervical, and the suprascapular arteries. | Anatomy_Gray. The vertebral artery is the first branch of the subclavian artery as it enters the root of the neck (Fig. 8.191). A large branch, arising from the first part of the subclavian artery medial to the anterior scalene muscle, it ascends and enters the foramen in the transverse process of vertebra CVI. Continuing to pass superiorly, the vertebral artery passes through the foramina of vertebrae CV to CI. At the superior border of vertebra CI, the artery turns medially and crosses the posterior arch of vertebra CI. From here it passes through the foramen magnum to enter the posterior cranial fossa. The second branch of the subclavian artery is the thyrocervical trunk (Fig. 8.191). It arises from the first part of the subclavian artery medial to the anterior scalene muscle, and divides into three branches—the inferior thyroid, the transverse cervical, and the suprascapular arteries. |
Anatomy_Gray_2458 | Anatomy_Gray | Inferior thyroid artery. The inferior thyroid artery (Fig. 8.191) is the superior continuation of the thyrocervical trunk. It ascends, anterior to the anterior scalene muscle, and eventually turns medially, crossing posterior to the carotid sheath and its contents and anterior to the vertebral artery. Reaching the posterior surface of the thyroid gland it supplies the thyroid gland. When the inferior thyroid artery turns medially, it gives off an important branch (the ascending cervical artery), which continues to ascend on the anterior surface of the prevertebral muscles, supplying these muscles and sending branches to the spinal cord. | Anatomy_Gray. Inferior thyroid artery. The inferior thyroid artery (Fig. 8.191) is the superior continuation of the thyrocervical trunk. It ascends, anterior to the anterior scalene muscle, and eventually turns medially, crossing posterior to the carotid sheath and its contents and anterior to the vertebral artery. Reaching the posterior surface of the thyroid gland it supplies the thyroid gland. When the inferior thyroid artery turns medially, it gives off an important branch (the ascending cervical artery), which continues to ascend on the anterior surface of the prevertebral muscles, supplying these muscles and sending branches to the spinal cord. |
Anatomy_Gray_2459 | Anatomy_Gray | Transverse cervical artery. The middle branch of the thyrocervical trunk is the transverse cervical artery (Fig. 8.191). This branch passes laterally, across the anterior surface of the anterior scalene muscle and the phrenic nerve, and enters and crosses the base of the posterior triangle of the neck. It continues to the deep surface of the trapezius muscle, where it divides into superficial and deep branches: The superficial branch continues on the deep surface of the trapezius muscle. The deep branch continues on the deep surface of the rhomboid muscles near the medial border of the scapula. | Anatomy_Gray. Transverse cervical artery. The middle branch of the thyrocervical trunk is the transverse cervical artery (Fig. 8.191). This branch passes laterally, across the anterior surface of the anterior scalene muscle and the phrenic nerve, and enters and crosses the base of the posterior triangle of the neck. It continues to the deep surface of the trapezius muscle, where it divides into superficial and deep branches: The superficial branch continues on the deep surface of the trapezius muscle. The deep branch continues on the deep surface of the rhomboid muscles near the medial border of the scapula. |
Anatomy_Gray_2460 | Anatomy_Gray | The superficial branch continues on the deep surface of the trapezius muscle. The deep branch continues on the deep surface of the rhomboid muscles near the medial border of the scapula. Suprascapular artery. The lowest branch of the thyrocervical trunk is the suprascapular artery (Fig. 8.191). This branch passes laterally, crossing anterior to the anterior scalene muscle, the phrenic nerve, the third part of the subclavian artery, and the trunks of the brachial plexus. At the superior border of the scapula, it crosses over the superior transverse scapular ligament and enters the supraspinatus fossa. The third branch of the subclavian artery is the internal thoracic artery (Fig. 8.191). This artery branches from the inferior edge of the subclavian artery and descends. | Anatomy_Gray. The superficial branch continues on the deep surface of the trapezius muscle. The deep branch continues on the deep surface of the rhomboid muscles near the medial border of the scapula. Suprascapular artery. The lowest branch of the thyrocervical trunk is the suprascapular artery (Fig. 8.191). This branch passes laterally, crossing anterior to the anterior scalene muscle, the phrenic nerve, the third part of the subclavian artery, and the trunks of the brachial plexus. At the superior border of the scapula, it crosses over the superior transverse scapular ligament and enters the supraspinatus fossa. The third branch of the subclavian artery is the internal thoracic artery (Fig. 8.191). This artery branches from the inferior edge of the subclavian artery and descends. |
Anatomy_Gray_2461 | Anatomy_Gray | The third branch of the subclavian artery is the internal thoracic artery (Fig. 8.191). This artery branches from the inferior edge of the subclavian artery and descends. It passes posterior to the clavicle and the large veins in the region and anterior to the pleural cavity. It enters the thoracic cavity posterior to the ribs and anterior to the transversus thoracis muscle and continues to descend giving off numerous branches. The final branch of the subclavian artery in the root of the neck is the costocervical trunk (Fig. 8.191). It arises in a slightly different position, depending on the side: On the left, it arises from the first part of the subclavian artery, just medial to the anterior scalene muscle. On the right, it arises from the second part of the subclavian artery. | Anatomy_Gray. The third branch of the subclavian artery is the internal thoracic artery (Fig. 8.191). This artery branches from the inferior edge of the subclavian artery and descends. It passes posterior to the clavicle and the large veins in the region and anterior to the pleural cavity. It enters the thoracic cavity posterior to the ribs and anterior to the transversus thoracis muscle and continues to descend giving off numerous branches. The final branch of the subclavian artery in the root of the neck is the costocervical trunk (Fig. 8.191). It arises in a slightly different position, depending on the side: On the left, it arises from the first part of the subclavian artery, just medial to the anterior scalene muscle. On the right, it arises from the second part of the subclavian artery. |
Anatomy_Gray_2462 | Anatomy_Gray | On the left, it arises from the first part of the subclavian artery, just medial to the anterior scalene muscle. On the right, it arises from the second part of the subclavian artery. On both sides, the costocervical trunk ascends and passes posteriorly over the dome of the pleural cavity and continues in a posterior direction behind the anterior scalene muscle. Eventually it divides into two branches—the deep cervical and the supreme intercostal arteries: The deep cervical artery ascends in the back of the neck and anastomoses with the descending branch of the occipital artery. The supreme intercostal artery descends anterior to rib I and divides to form the posterior intercostal arteries for the first two intercostal spaces. Numerous veins pass through the root of the neck. Small veins accompany each of the arteries described above, and large veins form major drainage channels. | Anatomy_Gray. On the left, it arises from the first part of the subclavian artery, just medial to the anterior scalene muscle. On the right, it arises from the second part of the subclavian artery. On both sides, the costocervical trunk ascends and passes posteriorly over the dome of the pleural cavity and continues in a posterior direction behind the anterior scalene muscle. Eventually it divides into two branches—the deep cervical and the supreme intercostal arteries: The deep cervical artery ascends in the back of the neck and anastomoses with the descending branch of the occipital artery. The supreme intercostal artery descends anterior to rib I and divides to form the posterior intercostal arteries for the first two intercostal spaces. Numerous veins pass through the root of the neck. Small veins accompany each of the arteries described above, and large veins form major drainage channels. |
Anatomy_Gray_2463 | Anatomy_Gray | Numerous veins pass through the root of the neck. Small veins accompany each of the arteries described above, and large veins form major drainage channels. The subclavian veins begin at the lateral margin of rib I as continuations of the axillary veins. Passing medially on each side, just anterior to the anterior scalene muscles, each subclavian vein is joined by the internal jugular vein to form the brachiocephalic veins. The only tributary to each subclavian vein is an external jugular vein. The veins accompanying the numerous arteries in this region empty into other veins. Several nerves and components of the nervous system pass through the root of the neck. | Anatomy_Gray. Numerous veins pass through the root of the neck. Small veins accompany each of the arteries described above, and large veins form major drainage channels. The subclavian veins begin at the lateral margin of rib I as continuations of the axillary veins. Passing medially on each side, just anterior to the anterior scalene muscles, each subclavian vein is joined by the internal jugular vein to form the brachiocephalic veins. The only tributary to each subclavian vein is an external jugular vein. The veins accompanying the numerous arteries in this region empty into other veins. Several nerves and components of the nervous system pass through the root of the neck. |
Anatomy_Gray_2464 | Anatomy_Gray | The veins accompanying the numerous arteries in this region empty into other veins. Several nerves and components of the nervous system pass through the root of the neck. The phrenic nerves are branches of the cervical plexus and arise on each side as contributions from the anterior rami of cervical nerves C3 to C5 come together. Passing around the upper lateral border of each anterior scalene muscle, the phrenic nerves continue inferiorly across the anterior surface of each anterior scalene muscle within the prevertebral layer of cervical fascia (Fig. 8.192). Leaving the lower edge of the anterior scalene muscle each phrenic nerve passes between the subclavian vein and artery to enter the thorax and continue to the diaphragm. The vagus nerves [X] descend through the neck within the carotid sheath, posterior to and just between the common carotid artery and the internal jugular vein. | Anatomy_Gray. The veins accompanying the numerous arteries in this region empty into other veins. Several nerves and components of the nervous system pass through the root of the neck. The phrenic nerves are branches of the cervical plexus and arise on each side as contributions from the anterior rami of cervical nerves C3 to C5 come together. Passing around the upper lateral border of each anterior scalene muscle, the phrenic nerves continue inferiorly across the anterior surface of each anterior scalene muscle within the prevertebral layer of cervical fascia (Fig. 8.192). Leaving the lower edge of the anterior scalene muscle each phrenic nerve passes between the subclavian vein and artery to enter the thorax and continue to the diaphragm. The vagus nerves [X] descend through the neck within the carotid sheath, posterior to and just between the common carotid artery and the internal jugular vein. |
Anatomy_Gray_2465 | Anatomy_Gray | The vagus nerves [X] descend through the neck within the carotid sheath, posterior to and just between the common carotid artery and the internal jugular vein. In the lower part of the neck, the vagus nerves [X] give off cardiac branches, which continue downward and medially, passing posterior to the subclavian arteries to disappear into the thorax. In the root of the neck, each vagus nerve [X] passes anterior to the subclavian artery and posterior to the subclavian vein as it enters the thorax (Fig. 8.192). The right and left recurrent laryngeal nerves are visible as they originate in (the right recurrent laryngeal nerve), or pass through (the left recurrent laryngeal nerve), the root of the neck. | Anatomy_Gray. The vagus nerves [X] descend through the neck within the carotid sheath, posterior to and just between the common carotid artery and the internal jugular vein. In the lower part of the neck, the vagus nerves [X] give off cardiac branches, which continue downward and medially, passing posterior to the subclavian arteries to disappear into the thorax. In the root of the neck, each vagus nerve [X] passes anterior to the subclavian artery and posterior to the subclavian vein as it enters the thorax (Fig. 8.192). The right and left recurrent laryngeal nerves are visible as they originate in (the right recurrent laryngeal nerve), or pass through (the left recurrent laryngeal nerve), the root of the neck. |
Anatomy_Gray_2466 | Anatomy_Gray | The right and left recurrent laryngeal nerves are visible as they originate in (the right recurrent laryngeal nerve), or pass through (the left recurrent laryngeal nerve), the root of the neck. The right recurrent laryngeal nerve is a branch of the right vagus nerve [X] as it reaches the lower edge of the first part of the subclavian artery in the root of the neck. It passes around the subclavian artery and upward and medially in a groove between the trachea and the esophagus as it heads to the larynx. The left recurrent laryngeal nerve is a branch of the left vagus nerve [X] as it crosses the arch of the aorta in the superior mediastinum. It passes below and behind the arch of the aorta and ascends beside the trachea to the larynx (Fig. 8.192). | Anatomy_Gray. The right and left recurrent laryngeal nerves are visible as they originate in (the right recurrent laryngeal nerve), or pass through (the left recurrent laryngeal nerve), the root of the neck. The right recurrent laryngeal nerve is a branch of the right vagus nerve [X] as it reaches the lower edge of the first part of the subclavian artery in the root of the neck. It passes around the subclavian artery and upward and medially in a groove between the trachea and the esophagus as it heads to the larynx. The left recurrent laryngeal nerve is a branch of the left vagus nerve [X] as it crosses the arch of the aorta in the superior mediastinum. It passes below and behind the arch of the aorta and ascends beside the trachea to the larynx (Fig. 8.192). |
Anatomy_Gray_2467 | Anatomy_Gray | Various components of the sympathetic nervous system are visible as they pass through the root of the neck (Fig. 8.193). These include: the cervical part of the sympathetic trunk, the ganglia associated with the cervical part of the sympathetic trunk, and cardiac nerves branching from the cervical part of the sympathetic trunk. The sympathetic trunks are two parallel cords that run from the base of the skull to the coccyx. Along the way they are punctuated by ganglia, which are collections of neuronal cell bodies outside the CNS. Cervical part of the sympathetic trunk The cervical part of the sympathetic trunk is anterior to the longus colli and longus capitis muscles, and posterior to the common carotid artery in the carotid sheath and the internal carotid artery. It is connected to each cervical spinal nerve by a gray ramus communicans (Fig. 8.194). There are no white rami communicantes in the cervical region. | Anatomy_Gray. Various components of the sympathetic nervous system are visible as they pass through the root of the neck (Fig. 8.193). These include: the cervical part of the sympathetic trunk, the ganglia associated with the cervical part of the sympathetic trunk, and cardiac nerves branching from the cervical part of the sympathetic trunk. The sympathetic trunks are two parallel cords that run from the base of the skull to the coccyx. Along the way they are punctuated by ganglia, which are collections of neuronal cell bodies outside the CNS. Cervical part of the sympathetic trunk The cervical part of the sympathetic trunk is anterior to the longus colli and longus capitis muscles, and posterior to the common carotid artery in the carotid sheath and the internal carotid artery. It is connected to each cervical spinal nerve by a gray ramus communicans (Fig. 8.194). There are no white rami communicantes in the cervical region. |
Anatomy_Gray_2468 | Anatomy_Gray | Three ganglia are usually described along the course of the sympathetic trunk in the cervical region, and in these ganglia ascending preganglionic sympathetic fibers from upper thoracic spinal cord levels synapse with postganglionic sympathetic fibers. The postganglionic sympathetic fibers are distributed in branches from these ganglia. Superior cervical ganglion. A very large superior cervical ganglion in the area of cervical vertebrae CI and CII marks the superior extent of the sympathetic trunk (Figs. 8.193 and 8.194). Its branches pass to: the internal carotid and external carotid arteries, forming plexuses around these vessels, cervical spinal nerves C1 to C4 through gray rami communicantes, the pharynx, and the heart as superior cardiac nerves. | Anatomy_Gray. Three ganglia are usually described along the course of the sympathetic trunk in the cervical region, and in these ganglia ascending preganglionic sympathetic fibers from upper thoracic spinal cord levels synapse with postganglionic sympathetic fibers. The postganglionic sympathetic fibers are distributed in branches from these ganglia. Superior cervical ganglion. A very large superior cervical ganglion in the area of cervical vertebrae CI and CII marks the superior extent of the sympathetic trunk (Figs. 8.193 and 8.194). Its branches pass to: the internal carotid and external carotid arteries, forming plexuses around these vessels, cervical spinal nerves C1 to C4 through gray rami communicantes, the pharynx, and the heart as superior cardiac nerves. |
Anatomy_Gray_2469 | Anatomy_Gray | Middle cervical ganglion. A second ganglion inferior to the superior cervical ganglion along the course of the sympathetic trunk (the middle cervical ganglion) is encountered at about the level of cervical vertebra CVI (Figs. 8.193 and 8.194). Branches from this ganglion pass to: cervical spinal nerves C5 and C6 through gray rami communicantes, and the heart as middle cardiac nerves. Inferior cervical ganglion. At the lower end of the cervical part of the sympathetic trunk is another ganglion (the inferior cervical ganglion), which becomes very large when it combines with the first thoracic ganglion and forms the cervicothoracic ganglion (stellate ganglion). The inferior cervical ganglion (Figs. 8.193 and 8.194) is anterior to the neck of rib I and the transverse process of cervical vertebra CVII, and posterior to the first part of the subclavian artery and the origin of the vertebral artery. | Anatomy_Gray. Middle cervical ganglion. A second ganglion inferior to the superior cervical ganglion along the course of the sympathetic trunk (the middle cervical ganglion) is encountered at about the level of cervical vertebra CVI (Figs. 8.193 and 8.194). Branches from this ganglion pass to: cervical spinal nerves C5 and C6 through gray rami communicantes, and the heart as middle cardiac nerves. Inferior cervical ganglion. At the lower end of the cervical part of the sympathetic trunk is another ganglion (the inferior cervical ganglion), which becomes very large when it combines with the first thoracic ganglion and forms the cervicothoracic ganglion (stellate ganglion). The inferior cervical ganglion (Figs. 8.193 and 8.194) is anterior to the neck of rib I and the transverse process of cervical vertebra CVII, and posterior to the first part of the subclavian artery and the origin of the vertebral artery. |
Anatomy_Gray_2470 | Anatomy_Gray | Branches from this ganglion pass to: spinal nerves C7 to T1 through gray rami communicantes, the vertebral artery, forming a plexus associated with this vessel, and the heart as inferior cardiac nerves. This ganglion may also receive white rami communicantes from thoracic spinal nerve T1, and occasionally, from T2. The thoracic duct is a major lymphatic channel that begins in the abdomen, passes superiorly through the thorax, and ends in the venous channels in the neck. It passes through the lower thoracic cavity in the midline with: the thoracic aorta on the left, the azygos vein on the right, and the esophagus anteriorly. | Anatomy_Gray. Branches from this ganglion pass to: spinal nerves C7 to T1 through gray rami communicantes, the vertebral artery, forming a plexus associated with this vessel, and the heart as inferior cardiac nerves. This ganglion may also receive white rami communicantes from thoracic spinal nerve T1, and occasionally, from T2. The thoracic duct is a major lymphatic channel that begins in the abdomen, passes superiorly through the thorax, and ends in the venous channels in the neck. It passes through the lower thoracic cavity in the midline with: the thoracic aorta on the left, the azygos vein on the right, and the esophagus anteriorly. |
Anatomy_Gray_2471 | Anatomy_Gray | It passes through the lower thoracic cavity in the midline with: the thoracic aorta on the left, the azygos vein on the right, and the esophagus anteriorly. At about the level of thoracic vertebra TV the thoracic duct passes to the left and continues to ascend just to the left of the esophagus. It passes through the superior mediastinum and enters the root of the neck to the left of the esophagus (Fig. 8.195). Arching laterally, it passes posterior to the carotid sheath and turns inferiorly in front of the thyrocervical trunk, the phrenic nerve, and the vertebral artery. | Anatomy_Gray. It passes through the lower thoracic cavity in the midline with: the thoracic aorta on the left, the azygos vein on the right, and the esophagus anteriorly. At about the level of thoracic vertebra TV the thoracic duct passes to the left and continues to ascend just to the left of the esophagus. It passes through the superior mediastinum and enters the root of the neck to the left of the esophagus (Fig. 8.195). Arching laterally, it passes posterior to the carotid sheath and turns inferiorly in front of the thyrocervical trunk, the phrenic nerve, and the vertebral artery. |
Anatomy_Gray_2472 | Anatomy_Gray | The thoracic duct terminates in the junction between the left internal jugular and the left subclavian veins (Fig. 8.195). Near its junction with the venous system it is joined by: the left jugular trunk, which drains lymph from the left side of the head and neck, the left subclavian trunk, which drains lymph from the left upper limb, and occasionally, the left bronchomediastinal trunk, which drains lymph from the left half of the thoracic structures (Fig. 8.196). A similar confluence of three lymphatic trunks occurs on the right side of the body. Emptying into the junction between the right internal jugular and right subclavian veins are: the right jugular trunk from the head and neck, the right subclavian trunk from the right upper limb, and occasionally, the right bronchomediastinal trunk carrying lymph from the structures in the right half of the thoracic cavity and the right upper intercostal spaces (Fig. 8.196). | Anatomy_Gray. The thoracic duct terminates in the junction between the left internal jugular and the left subclavian veins (Fig. 8.195). Near its junction with the venous system it is joined by: the left jugular trunk, which drains lymph from the left side of the head and neck, the left subclavian trunk, which drains lymph from the left upper limb, and occasionally, the left bronchomediastinal trunk, which drains lymph from the left half of the thoracic structures (Fig. 8.196). A similar confluence of three lymphatic trunks occurs on the right side of the body. Emptying into the junction between the right internal jugular and right subclavian veins are: the right jugular trunk from the head and neck, the right subclavian trunk from the right upper limb, and occasionally, the right bronchomediastinal trunk carrying lymph from the structures in the right half of the thoracic cavity and the right upper intercostal spaces (Fig. 8.196). |
Anatomy_Gray_2473 | Anatomy_Gray | There is variability in how these trunks enter the veins. They may combine into a single right lymphatic duct to enter the venous system or enter as three separate trunks. Lymphatics of the neck A description of the organization of the lymphatic system in the neck becomes a summary of the lymphatic system in the head and neck. It is impossible to separate the two regions. The components of this system include superficial nodes around the head, superficial cervical nodes along the external jugular vein, and deep cervical nodes forming a chain along the internal jugular vein (Fig. 8.197). The basic pattern of drainage is for superficial lymphatic vessels to drain to the superficial nodes. Some of these drain to the superficial cervical nodes on their way to the deep cervical nodes and others drain directly to the deep cervical nodes. | Anatomy_Gray. There is variability in how these trunks enter the veins. They may combine into a single right lymphatic duct to enter the venous system or enter as three separate trunks. Lymphatics of the neck A description of the organization of the lymphatic system in the neck becomes a summary of the lymphatic system in the head and neck. It is impossible to separate the two regions. The components of this system include superficial nodes around the head, superficial cervical nodes along the external jugular vein, and deep cervical nodes forming a chain along the internal jugular vein (Fig. 8.197). The basic pattern of drainage is for superficial lymphatic vessels to drain to the superficial nodes. Some of these drain to the superficial cervical nodes on their way to the deep cervical nodes and others drain directly to the deep cervical nodes. |
Anatomy_Gray_2474 | Anatomy_Gray | Five groups of superficial lymph nodes form a ring around the head and are primarily responsible for the lymphatic drainage of the face and scalp. Their pattern of drainage is very similar to the area of distribution of the arteries near their location. | Anatomy_Gray. Five groups of superficial lymph nodes form a ring around the head and are primarily responsible for the lymphatic drainage of the face and scalp. Their pattern of drainage is very similar to the area of distribution of the arteries near their location. |
Anatomy_Gray_2475 | Anatomy_Gray | Beginning posteriorly these groups (Fig. 8.197) are: occipital nodes near the attachment of the trapezius muscle to the skull and associated with the occipital artery—lymphatic drainage is from the posterior scalp and neck; mastoid nodes (retro-auricular/posterior auricular nodes) posterior to the ear near the attachment of the sternocleidomastoid muscle and associated with the posterior auricular artery—lymphatic drainage is from the posterolateral half of the scalp; pre-auricular and parotid nodes anterior to the ear and associated with the superficial temporal and transverse facial arteries—lymphatic drainage is from the anterior surface of the auricle, the anterolateral scalp, the upper half of the face, the eyelids, and the cheeks; submandibular nodes inferior to the body of the mandible and associated with the facial artery—lymphatic drainage is from structures along the path of the facial artery as high as the forehead, as well as the gingivae, the teeth, and the tongue; | Anatomy_Gray. Beginning posteriorly these groups (Fig. 8.197) are: occipital nodes near the attachment of the trapezius muscle to the skull and associated with the occipital artery—lymphatic drainage is from the posterior scalp and neck; mastoid nodes (retro-auricular/posterior auricular nodes) posterior to the ear near the attachment of the sternocleidomastoid muscle and associated with the posterior auricular artery—lymphatic drainage is from the posterolateral half of the scalp; pre-auricular and parotid nodes anterior to the ear and associated with the superficial temporal and transverse facial arteries—lymphatic drainage is from the anterior surface of the auricle, the anterolateral scalp, the upper half of the face, the eyelids, and the cheeks; submandibular nodes inferior to the body of the mandible and associated with the facial artery—lymphatic drainage is from structures along the path of the facial artery as high as the forehead, as well as the gingivae, the teeth, and the tongue; |
Anatomy_Gray_2476 | Anatomy_Gray | mandible and associated with the facial artery—lymphatic drainage is from structures along the path of the facial artery as high as the forehead, as well as the gingivae, the teeth, and the tongue; submental nodes inferior and posterior to the chin—lymphatic drainage is from the center part of the lower lip, the chin, the floor of the mouth, the tip of the tongue, and the lower incisor teeth. | Anatomy_Gray. mandible and associated with the facial artery—lymphatic drainage is from structures along the path of the facial artery as high as the forehead, as well as the gingivae, the teeth, and the tongue; submental nodes inferior and posterior to the chin—lymphatic drainage is from the center part of the lower lip, the chin, the floor of the mouth, the tip of the tongue, and the lower incisor teeth. |
Anatomy_Gray_2477 | Anatomy_Gray | Lymphatic flow from these superficial lymph nodes passes in several directions: Drainage from the occipital and mastoid nodes passes to the superficial cervical nodes along the external jugular vein. Drainage from the pre-auricular and parotid nodes, the submandibular nodes, and the submental nodes passes to the deep cervical nodes. The superficial cervical nodes are a collection of lymph nodes along the external jugular vein on the superficial surface of the sternocleidomastoid muscle (Fig. 8.197). They primarily receive lymphatic drainage from the posterior and posterolateral regions of the scalp through the occipital and mastoid nodes, and send lymphatic vessels in the direction of the deep cervical nodes. | Anatomy_Gray. Lymphatic flow from these superficial lymph nodes passes in several directions: Drainage from the occipital and mastoid nodes passes to the superficial cervical nodes along the external jugular vein. Drainage from the pre-auricular and parotid nodes, the submandibular nodes, and the submental nodes passes to the deep cervical nodes. The superficial cervical nodes are a collection of lymph nodes along the external jugular vein on the superficial surface of the sternocleidomastoid muscle (Fig. 8.197). They primarily receive lymphatic drainage from the posterior and posterolateral regions of the scalp through the occipital and mastoid nodes, and send lymphatic vessels in the direction of the deep cervical nodes. |
Anatomy_Gray_2478 | Anatomy_Gray | The deep cervical nodes are a collection of lymph nodes that form a chain along the internal jugular vein (Fig. 8.197). They are divided into upper and lower groups where the intermediate tendon of the omohyoid muscle crosses the common carotid artery and the internal jugular vein. The most superior node in the upper deep cervical group is the jugulodigastric node (Fig. 8.197). This large node is where the posterior belly of the digastric muscle crosses the internal jugular vein and receives lymphatic drainage from the tonsils and tonsillar region. Another large node, usually associated with the lower deep cervical group because it is at or just inferior to the intermediate tendon of the omohyoid muscle, is the jugulo-omohyoid node (Fig. 8.197). This node receives lymphatic drainage from the tongue. The deep cervical nodes eventually receive all lymphatic drainage from the head and neck either directly or through regional groups of nodes. | Anatomy_Gray. The deep cervical nodes are a collection of lymph nodes that form a chain along the internal jugular vein (Fig. 8.197). They are divided into upper and lower groups where the intermediate tendon of the omohyoid muscle crosses the common carotid artery and the internal jugular vein. The most superior node in the upper deep cervical group is the jugulodigastric node (Fig. 8.197). This large node is where the posterior belly of the digastric muscle crosses the internal jugular vein and receives lymphatic drainage from the tonsils and tonsillar region. Another large node, usually associated with the lower deep cervical group because it is at or just inferior to the intermediate tendon of the omohyoid muscle, is the jugulo-omohyoid node (Fig. 8.197). This node receives lymphatic drainage from the tongue. The deep cervical nodes eventually receive all lymphatic drainage from the head and neck either directly or through regional groups of nodes. |
Anatomy_Gray_2479 | Anatomy_Gray | The deep cervical nodes eventually receive all lymphatic drainage from the head and neck either directly or through regional groups of nodes. From the deep cervical nodes, lymphatic vessels form the right and left jugular trunks, which empty into the right lymphatic duct on the right side or the thoracic duct on the left side. The pharynx is a musculofascial half-cylinder that links the oral and nasal cavities in the head to the larynx and esophagus in the neck (Fig. 8.198). The pharyngeal cavity is a common pathway for air and food. The pharynx is attached above to the base of the skull and is continuous below, approximately at the level of vertebra CVI, with the top of the esophagus. The walls of the pharynx are attached anteriorly to the margins of the nasal cavities, oral cavity, and larynx. Based on these anterior relationships the pharynx is subdivided into three regions, the nasopharynx, oropharynx, and laryngopharynx: | Anatomy_Gray. The deep cervical nodes eventually receive all lymphatic drainage from the head and neck either directly or through regional groups of nodes. From the deep cervical nodes, lymphatic vessels form the right and left jugular trunks, which empty into the right lymphatic duct on the right side or the thoracic duct on the left side. The pharynx is a musculofascial half-cylinder that links the oral and nasal cavities in the head to the larynx and esophagus in the neck (Fig. 8.198). The pharyngeal cavity is a common pathway for air and food. The pharynx is attached above to the base of the skull and is continuous below, approximately at the level of vertebra CVI, with the top of the esophagus. The walls of the pharynx are attached anteriorly to the margins of the nasal cavities, oral cavity, and larynx. Based on these anterior relationships the pharynx is subdivided into three regions, the nasopharynx, oropharynx, and laryngopharynx: |
Anatomy_Gray_2480 | Anatomy_Gray | The posterior apertures (choanae) of the nasal cavities open into the nasopharynx. The posterior opening of the oral cavity (oropharyngeal isthmus) opens into the oropharynx. The superior aperture of the larynx (laryngeal inlet) opens into the laryngopharynx. In addition to these openings, the pharyngeal cavity is related anteriorly to the posterior one-third of the tongue and to the posterior aspect of the larynx. The pharyngotympanic tubes open into the lateral walls of the nasopharynx. Lingual, pharyngeal, and palatine tonsils are on the deep surface of the pharyngeal walls. The pharynx is separated from the posteriorly positioned vertebral column by a thin retropharyngeal space containing loose connective tissue. | Anatomy_Gray. The posterior apertures (choanae) of the nasal cavities open into the nasopharynx. The posterior opening of the oral cavity (oropharyngeal isthmus) opens into the oropharynx. The superior aperture of the larynx (laryngeal inlet) opens into the laryngopharynx. In addition to these openings, the pharyngeal cavity is related anteriorly to the posterior one-third of the tongue and to the posterior aspect of the larynx. The pharyngotympanic tubes open into the lateral walls of the nasopharynx. Lingual, pharyngeal, and palatine tonsils are on the deep surface of the pharyngeal walls. The pharynx is separated from the posteriorly positioned vertebral column by a thin retropharyngeal space containing loose connective tissue. |
Anatomy_Gray_2481 | Anatomy_Gray | The pharynx is separated from the posteriorly positioned vertebral column by a thin retropharyngeal space containing loose connective tissue. Although the soft palate is generally considered as part of the roof of the oral cavity, it is also related to the pharynx. The soft palate is attached to the posterior margin of the hard palate and is a type of “flutter valve” that can: swing up (elevate) to close the pharyngeal isthmus, and seal off the nasopharynx from the oropharynx, and swing down (depress) to close the oropharyngeal isthmus and seal off the oral cavity from the oropharynx. | Anatomy_Gray. The pharynx is separated from the posteriorly positioned vertebral column by a thin retropharyngeal space containing loose connective tissue. Although the soft palate is generally considered as part of the roof of the oral cavity, it is also related to the pharynx. The soft palate is attached to the posterior margin of the hard palate and is a type of “flutter valve” that can: swing up (elevate) to close the pharyngeal isthmus, and seal off the nasopharynx from the oropharynx, and swing down (depress) to close the oropharyngeal isthmus and seal off the oral cavity from the oropharynx. |
Anatomy_Gray_2482 | Anatomy_Gray | The superior and anterior margins of the pharyngeal wall are attached to bone and cartilage, and to ligaments. The two sides of the pharyngeal wall are welded together posteriorly in the midline by a vertically oriented cord-like ligament (the pharyngeal raphe). This connective tissue structure descends from the pharyngeal tubercle on the base of the skull to the level of cervical vertebra CVI where the raphe blends with connective tissue in the posterior wall of the esophagus. | Anatomy_Gray. The superior and anterior margins of the pharyngeal wall are attached to bone and cartilage, and to ligaments. The two sides of the pharyngeal wall are welded together posteriorly in the midline by a vertically oriented cord-like ligament (the pharyngeal raphe). This connective tissue structure descends from the pharyngeal tubercle on the base of the skull to the level of cervical vertebra CVI where the raphe blends with connective tissue in the posterior wall of the esophagus. |
Anatomy_Gray_2483 | Anatomy_Gray | There is an irregular C-shaped line of pharyngeal wall attachment on the base of the skull (Fig. 8.200). The open part of the C faces the nasal cavities. Each arm of the C begins at the posterior margin of the medial plate of the pterygoid process of the sphenoid bone, just inferior to the cartilaginous part of the pharyngotympanic tube. The line crosses inferior to the pharyngotympanic tube and then passes onto the petrous part of the temporal bone where it is just medial to the roughening for the attachment of one of the muscles (levator veli palatini) of the soft palate. From here, the line swings medially onto the occipital bone and joins the line from the other side at a prominent elevation of bone in the midline (the pharyngeal tubercle). Anterior vertical line of attachment for the lateral pharyngeal walls | Anatomy_Gray. There is an irregular C-shaped line of pharyngeal wall attachment on the base of the skull (Fig. 8.200). The open part of the C faces the nasal cavities. Each arm of the C begins at the posterior margin of the medial plate of the pterygoid process of the sphenoid bone, just inferior to the cartilaginous part of the pharyngotympanic tube. The line crosses inferior to the pharyngotympanic tube and then passes onto the petrous part of the temporal bone where it is just medial to the roughening for the attachment of one of the muscles (levator veli palatini) of the soft palate. From here, the line swings medially onto the occipital bone and joins the line from the other side at a prominent elevation of bone in the midline (the pharyngeal tubercle). Anterior vertical line of attachment for the lateral pharyngeal walls |
Anatomy_Gray_2484 | Anatomy_Gray | Anterior vertical line of attachment for the lateral pharyngeal walls The vertical line of attachment for the lateral pharyngeal walls to structures related to the nasal and oral cavities and larynx is discontinuous and in three parts (Fig. 8.201). On each side, the anterior line of attachment of the lateral pharyngeal wall begins superiorly on the posterior edge of the medial pterygoid plate of the sphenoid bone just inferior to where the pharyngotympanic tube lies against this plate. It continues inferiorly along the edge of the medial plate of the pterygoid process and onto the pterygoid hamulus. From this point, the line descends along the pterygomandibular raphe to the mandible where this part of the line terminates. | Anatomy_Gray. Anterior vertical line of attachment for the lateral pharyngeal walls The vertical line of attachment for the lateral pharyngeal walls to structures related to the nasal and oral cavities and larynx is discontinuous and in three parts (Fig. 8.201). On each side, the anterior line of attachment of the lateral pharyngeal wall begins superiorly on the posterior edge of the medial pterygoid plate of the sphenoid bone just inferior to where the pharyngotympanic tube lies against this plate. It continues inferiorly along the edge of the medial plate of the pterygoid process and onto the pterygoid hamulus. From this point, the line descends along the pterygomandibular raphe to the mandible where this part of the line terminates. |
Anatomy_Gray_2485 | Anatomy_Gray | The pterygomandibular raphe is a linear cord-like connective tissue ligament that spans the distance between the tip of the pterygoid hamulus and a triangular roughening immediately posterior to the third molar on the mandible. It joins a muscle of the lateral pharyngeal wall (superior constrictor) with a muscle of the lateral wall of the oral cavity (buccinator). The second part of the line of attachment of the lateral pharyngeal wall is related to the hyoid bone. It begins on the lower aspect of the stylohyoid ligament, which connects the tip of the styloid process of the temporal bone to the lesser horn of the hyoid bone. The line continues onto the lesser horn and then turns and runs posteriorly along the entire upper surface of the greater horn of the hyoid where it terminates. | Anatomy_Gray. The pterygomandibular raphe is a linear cord-like connective tissue ligament that spans the distance between the tip of the pterygoid hamulus and a triangular roughening immediately posterior to the third molar on the mandible. It joins a muscle of the lateral pharyngeal wall (superior constrictor) with a muscle of the lateral wall of the oral cavity (buccinator). The second part of the line of attachment of the lateral pharyngeal wall is related to the hyoid bone. It begins on the lower aspect of the stylohyoid ligament, which connects the tip of the styloid process of the temporal bone to the lesser horn of the hyoid bone. The line continues onto the lesser horn and then turns and runs posteriorly along the entire upper surface of the greater horn of the hyoid where it terminates. |
Anatomy_Gray_2486 | Anatomy_Gray | The most inferior and third part of the line of attachment of the lateral pharyngeal wall begins superiorly on the superior tubercle of the thyroid cartilage, and descends along the oblique line to the inferior tubercle. From the inferior tubercle, the line of attachment continues over the cricothyroid muscle along a tendinous thickening of fascia to the cricoid cartilage where it terminates. The pharyngeal wall is formed by skeletal muscles and by fascia. Gaps between the muscles are reinforced by the fascia and provide routes for structures to pass through the wall. The muscles of the pharynx are organized into two groups based on the orientation of muscle fibers. The constrictor muscles have fibers oriented in a circular direction relative to the pharyngeal wall, whereas the longitudinal muscles have fibers oriented vertically. | Anatomy_Gray. The most inferior and third part of the line of attachment of the lateral pharyngeal wall begins superiorly on the superior tubercle of the thyroid cartilage, and descends along the oblique line to the inferior tubercle. From the inferior tubercle, the line of attachment continues over the cricothyroid muscle along a tendinous thickening of fascia to the cricoid cartilage where it terminates. The pharyngeal wall is formed by skeletal muscles and by fascia. Gaps between the muscles are reinforced by the fascia and provide routes for structures to pass through the wall. The muscles of the pharynx are organized into two groups based on the orientation of muscle fibers. The constrictor muscles have fibers oriented in a circular direction relative to the pharyngeal wall, whereas the longitudinal muscles have fibers oriented vertically. |
Anatomy_Gray_2487 | Anatomy_Gray | The constrictor muscles have fibers oriented in a circular direction relative to the pharyngeal wall, whereas the longitudinal muscles have fibers oriented vertically. The three constrictor muscles on each side are major contributors to the structure of the pharyngeal wall (Fig. 8.202 and Table 8.17) and their names indicate their position—superior, middle, and inferior constrictor muscles. Posteriorly, the muscles from each side are joined together by the pharyngeal raphe. Anteriorly, these muscles attach to bones, cartilages, and ligaments related to the lateral margins of the nasal and oral cavities and the larynx. The constrictor muscles overlap each other in a fashion resembling the walls of three flower pots stacked one on the other. The inferior constrictors overlap the lower margins of the middle constrictors and, in the same way, the middle constrictors overlap the superior constrictors. Collectively, the muscles constrict or narrow the pharyngeal cavity. | Anatomy_Gray. The constrictor muscles have fibers oriented in a circular direction relative to the pharyngeal wall, whereas the longitudinal muscles have fibers oriented vertically. The three constrictor muscles on each side are major contributors to the structure of the pharyngeal wall (Fig. 8.202 and Table 8.17) and their names indicate their position—superior, middle, and inferior constrictor muscles. Posteriorly, the muscles from each side are joined together by the pharyngeal raphe. Anteriorly, these muscles attach to bones, cartilages, and ligaments related to the lateral margins of the nasal and oral cavities and the larynx. The constrictor muscles overlap each other in a fashion resembling the walls of three flower pots stacked one on the other. The inferior constrictors overlap the lower margins of the middle constrictors and, in the same way, the middle constrictors overlap the superior constrictors. Collectively, the muscles constrict or narrow the pharyngeal cavity. |
Anatomy_Gray_2488 | Anatomy_Gray | Collectively, the muscles constrict or narrow the pharyngeal cavity. When the constrictor muscles contract sequentially from top to bottom, as in swallowing, they move a bolus of food through the pharynx and into the esophagus. All of the constrictors are innervated by the pharyngeal branch of the vagus nerve [X]. The superior constrictor muscles together bracket the upper part of the pharyngeal cavity (Fig. 8.202). Each muscle is attached anteriorly to the pterygoid hamulus, pterygomandibular raphe, and adjacent bone of the mandible. From these attachments, the muscle fans out posteriorly and joins with its partner muscle from the other side at the pharyngeal raphe. A special band of muscle (the palatopharyngeal sphincter) originates from the anterolateral surface of the soft palate and circles the inner aspect of the pharyngeal wall, blending with the inner aspect of the superior constrictor. | Anatomy_Gray. Collectively, the muscles constrict or narrow the pharyngeal cavity. When the constrictor muscles contract sequentially from top to bottom, as in swallowing, they move a bolus of food through the pharynx and into the esophagus. All of the constrictors are innervated by the pharyngeal branch of the vagus nerve [X]. The superior constrictor muscles together bracket the upper part of the pharyngeal cavity (Fig. 8.202). Each muscle is attached anteriorly to the pterygoid hamulus, pterygomandibular raphe, and adjacent bone of the mandible. From these attachments, the muscle fans out posteriorly and joins with its partner muscle from the other side at the pharyngeal raphe. A special band of muscle (the palatopharyngeal sphincter) originates from the anterolateral surface of the soft palate and circles the inner aspect of the pharyngeal wall, blending with the inner aspect of the superior constrictor. |
Anatomy_Gray_2489 | Anatomy_Gray | When the superior constrictor constricts during swallowing, it forms a prominent ridge on the deep aspect of the pharyngeal wall that catches the margin of the elevated soft palate, which then seals closed the pharyngeal isthmus between the nasopharynx and oropharynx. The middle constrictor muscles are attached to the lower aspect of the stylohyoid ligament, the lesser horn of the hyoid bone, and the entire upper surface of the greater horn of the hyoid (Fig. 8.202). Like the superior constrictors, the middle constrictor muscles fan out posteriorly and attach to the pharyngeal raphe. The posterior part of the middle constrictors overlaps the superior constrictors. The inferior constrictor muscles attach anteriorly to the oblique line of the thyroid cartilage, the cricoid cartilage, and a ligament that spans between these two attachments to cartilage and crosses the cricothyroid muscle (Fig. 8.202). | Anatomy_Gray. When the superior constrictor constricts during swallowing, it forms a prominent ridge on the deep aspect of the pharyngeal wall that catches the margin of the elevated soft palate, which then seals closed the pharyngeal isthmus between the nasopharynx and oropharynx. The middle constrictor muscles are attached to the lower aspect of the stylohyoid ligament, the lesser horn of the hyoid bone, and the entire upper surface of the greater horn of the hyoid (Fig. 8.202). Like the superior constrictors, the middle constrictor muscles fan out posteriorly and attach to the pharyngeal raphe. The posterior part of the middle constrictors overlaps the superior constrictors. The inferior constrictor muscles attach anteriorly to the oblique line of the thyroid cartilage, the cricoid cartilage, and a ligament that spans between these two attachments to cartilage and crosses the cricothyroid muscle (Fig. 8.202). |
Anatomy_Gray_2490 | Anatomy_Gray | Like the other constrictor muscles, the inferior constrictor muscles spread out posteriorly and attach to the pharyngeal raphe. The posterior part of the inferior constrictors overlaps the middle constrictors. Inferiorly, the muscle fibers blend with and attach into the wall of the esophagus. The parts of the inferior constrictors attached to the cricoid cartilage bracket the narrowest part of the pharyngeal cavity. The three longitudinal muscles of the pharyngeal wall (Fig. 8.203 and Table 8.18) are named according to their origins—stylopharyngeus from the styloid process of the temporal bone, salpingopharyngeus from the cartilaginous part of the pharyngotympanic tube (salpinx is Greek for “tube”), and palatopharyngeus from the soft palate. From their sites of origin, these muscles descend and attach into the pharyngeal wall. | Anatomy_Gray. Like the other constrictor muscles, the inferior constrictor muscles spread out posteriorly and attach to the pharyngeal raphe. The posterior part of the inferior constrictors overlaps the middle constrictors. Inferiorly, the muscle fibers blend with and attach into the wall of the esophagus. The parts of the inferior constrictors attached to the cricoid cartilage bracket the narrowest part of the pharyngeal cavity. The three longitudinal muscles of the pharyngeal wall (Fig. 8.203 and Table 8.18) are named according to their origins—stylopharyngeus from the styloid process of the temporal bone, salpingopharyngeus from the cartilaginous part of the pharyngotympanic tube (salpinx is Greek for “tube”), and palatopharyngeus from the soft palate. From their sites of origin, these muscles descend and attach into the pharyngeal wall. |
Anatomy_Gray_2491 | Anatomy_Gray | The longitudinal muscles elevate the pharyngeal wall, or during swallowing, pull the pharyngeal wall up and over a bolus of food being moved through the pharynx and into the esophagus. The cylindrical stylopharyngeus muscle (Fig. 8.203A) originates from the base of the medial surface of the styloid process of the temporal bone and descends between the superior and middle constrictor muscles to fan out on, and blend with, the deep surface of the pharyngeal wall. It is innervated by the glossopharyngeal nerve [IX]. The salpingopharyngeus (Fig. 8.203B) is a small muscle originating from the inferior aspect of the pharyngotympanic tube, descending on, and blending into, the deep surface of the pharyngeal wall. It is innervated by the vagus nerve [X]. | Anatomy_Gray. The longitudinal muscles elevate the pharyngeal wall, or during swallowing, pull the pharyngeal wall up and over a bolus of food being moved through the pharynx and into the esophagus. The cylindrical stylopharyngeus muscle (Fig. 8.203A) originates from the base of the medial surface of the styloid process of the temporal bone and descends between the superior and middle constrictor muscles to fan out on, and blend with, the deep surface of the pharyngeal wall. It is innervated by the glossopharyngeal nerve [IX]. The salpingopharyngeus (Fig. 8.203B) is a small muscle originating from the inferior aspect of the pharyngotympanic tube, descending on, and blending into, the deep surface of the pharyngeal wall. It is innervated by the vagus nerve [X]. |
Anatomy_Gray_2492 | Anatomy_Gray | The palatopharyngeus (Fig. 8.203B), in addition to being a muscle of the pharynx, is also a muscle of the soft palate (see pp. 1098–1099). It is attached to the upper surface of the palatine aponeurosis, and passes posteriorly and inferiorly to blend with the deep surface of the pharyngeal wall. The palatopharyngeus forms an important fold in the overlying mucosa (the palatopharyngeal arch). This arch is visible through the oral cavity and is a landmark for finding the palatine tonsil, which is immediately anterior to it on the oropharyngeal wall. In addition to elevating the pharynx, the palatopharyngeus participates in closing the oropharyngeal isthmus by depressing the palate and moving the palatopharyngeal fold toward the midline. The palatopharyngeus is innervated by the vagus nerve [X]. The pharyngeal fascia is separated into two layers, which sandwich the pharyngeal muscles between them: | Anatomy_Gray. The palatopharyngeus (Fig. 8.203B), in addition to being a muscle of the pharynx, is also a muscle of the soft palate (see pp. 1098–1099). It is attached to the upper surface of the palatine aponeurosis, and passes posteriorly and inferiorly to blend with the deep surface of the pharyngeal wall. The palatopharyngeus forms an important fold in the overlying mucosa (the palatopharyngeal arch). This arch is visible through the oral cavity and is a landmark for finding the palatine tonsil, which is immediately anterior to it on the oropharyngeal wall. In addition to elevating the pharynx, the palatopharyngeus participates in closing the oropharyngeal isthmus by depressing the palate and moving the palatopharyngeal fold toward the midline. The palatopharyngeus is innervated by the vagus nerve [X]. The pharyngeal fascia is separated into two layers, which sandwich the pharyngeal muscles between them: |
Anatomy_Gray_2493 | Anatomy_Gray | The palatopharyngeus is innervated by the vagus nerve [X]. The pharyngeal fascia is separated into two layers, which sandwich the pharyngeal muscles between them: A thin layer (buccopharyngeal fascia) coats the outside of the muscular part of the wall and is a component of the pretracheal layer of cervical fascia (see p. 991). A much thicker layer (pharyngobasilar fascia) lines the inner surface. The fascia reinforces the pharyngeal wall where muscle is deficient. This is particularly evident above the level of the superior constrictor where the pharyngeal wall is formed almost entirely of fascia (Fig. 8.203). This part of the wall is reinforced externally by muscles of the soft palate (tensor and levator veli palatini). Gaps in the pharyngeal wall and structures passing through them Gaps between muscles of the pharyngeal wall provide important routes for muscles and neurovascular tissues (Fig. 8.204). | Anatomy_Gray. The palatopharyngeus is innervated by the vagus nerve [X]. The pharyngeal fascia is separated into two layers, which sandwich the pharyngeal muscles between them: A thin layer (buccopharyngeal fascia) coats the outside of the muscular part of the wall and is a component of the pretracheal layer of cervical fascia (see p. 991). A much thicker layer (pharyngobasilar fascia) lines the inner surface. The fascia reinforces the pharyngeal wall where muscle is deficient. This is particularly evident above the level of the superior constrictor where the pharyngeal wall is formed almost entirely of fascia (Fig. 8.203). This part of the wall is reinforced externally by muscles of the soft palate (tensor and levator veli palatini). Gaps in the pharyngeal wall and structures passing through them Gaps between muscles of the pharyngeal wall provide important routes for muscles and neurovascular tissues (Fig. 8.204). |
Anatomy_Gray_2494 | Anatomy_Gray | Gaps in the pharyngeal wall and structures passing through them Gaps between muscles of the pharyngeal wall provide important routes for muscles and neurovascular tissues (Fig. 8.204). Above the margin of the superior constrictor, the pharyngeal wall is deficient in muscle and completed by pharyngeal fascia. The tensor and levator veli palatini muscles of the soft palate initially descend from the base of the skull and are lateral to the pharyngeal fascia. In this position, they reinforce the pharyngeal wall: The levator veli palatini passes through the pharyngeal fascia inferior to the pharyngotympanic tube and enters the soft palate. The tendon of the tensor veli palatini turns medially around the pterygoid hamulus and passes through the origin of the buccinator muscle to enter the soft palate. | Anatomy_Gray. Gaps in the pharyngeal wall and structures passing through them Gaps between muscles of the pharyngeal wall provide important routes for muscles and neurovascular tissues (Fig. 8.204). Above the margin of the superior constrictor, the pharyngeal wall is deficient in muscle and completed by pharyngeal fascia. The tensor and levator veli palatini muscles of the soft palate initially descend from the base of the skull and are lateral to the pharyngeal fascia. In this position, they reinforce the pharyngeal wall: The levator veli palatini passes through the pharyngeal fascia inferior to the pharyngotympanic tube and enters the soft palate. The tendon of the tensor veli palatini turns medially around the pterygoid hamulus and passes through the origin of the buccinator muscle to enter the soft palate. |
Anatomy_Gray_2495 | Anatomy_Gray | The tendon of the tensor veli palatini turns medially around the pterygoid hamulus and passes through the origin of the buccinator muscle to enter the soft palate. One of the largest and most important apertures in the pharyngeal wall is between the superior and middle constrictor muscles of the pharynx and the posterior border of the mylohyoid muscle, which forms the floor of the mouth (Fig. 8.204). This triangular-shaped gap (oropharyngeal triangle) not only enables the stylopharyngeus to slip into the pharyngeal wall, but also allows muscles, nerves, and vessels to pass between regions lateral to the pharyngeal wall and the oral cavity, particularly to the tongue. The gap between the middle and inferior constrictor muscles allows the internal laryngeal vessels and nerve access to the aperture in the thyrohyoid membrane to enter the larynx. | Anatomy_Gray. The tendon of the tensor veli palatini turns medially around the pterygoid hamulus and passes through the origin of the buccinator muscle to enter the soft palate. One of the largest and most important apertures in the pharyngeal wall is between the superior and middle constrictor muscles of the pharynx and the posterior border of the mylohyoid muscle, which forms the floor of the mouth (Fig. 8.204). This triangular-shaped gap (oropharyngeal triangle) not only enables the stylopharyngeus to slip into the pharyngeal wall, but also allows muscles, nerves, and vessels to pass between regions lateral to the pharyngeal wall and the oral cavity, particularly to the tongue. The gap between the middle and inferior constrictor muscles allows the internal laryngeal vessels and nerve access to the aperture in the thyrohyoid membrane to enter the larynx. |
Anatomy_Gray_2496 | Anatomy_Gray | The gap between the middle and inferior constrictor muscles allows the internal laryngeal vessels and nerve access to the aperture in the thyrohyoid membrane to enter the larynx. The recurrent laryngeal nerves and accompanying inferior laryngeal vessels enter the larynx posterior to the inferior horn of the thyroid cartilage deep to the inferior margin of the inferior constrictor muscle. The nasopharynx is behind the posterior apertures (choanae) of the nasal cavities and above the level of the soft palate (Fig. 8.205). Its ceiling is formed by the sloping base of the skull and consists of the posterior part of the body of the sphenoid bone and the basal part of the occipital bone. The ceiling and lateral walls of the nasopharynx form a domed vault at the top of the pharyngeal cavity that is always open. | Anatomy_Gray. The gap between the middle and inferior constrictor muscles allows the internal laryngeal vessels and nerve access to the aperture in the thyrohyoid membrane to enter the larynx. The recurrent laryngeal nerves and accompanying inferior laryngeal vessels enter the larynx posterior to the inferior horn of the thyroid cartilage deep to the inferior margin of the inferior constrictor muscle. The nasopharynx is behind the posterior apertures (choanae) of the nasal cavities and above the level of the soft palate (Fig. 8.205). Its ceiling is formed by the sloping base of the skull and consists of the posterior part of the body of the sphenoid bone and the basal part of the occipital bone. The ceiling and lateral walls of the nasopharynx form a domed vault at the top of the pharyngeal cavity that is always open. |
Anatomy_Gray_2497 | Anatomy_Gray | The cavity of the nasopharynx is continuous below with the cavity of the oropharynx at the pharyngeal isthmus. The position of the pharyngeal isthmus is marked on the pharyngeal wall by a mucosal fold caused by the underlying palatopharyngeal sphincter, which is part of the superior constrictor muscle. Elevation of the soft palate and constriction of the palatopharyngeal sphincter closes the pharyngeal isthmus during swallowing and separates the nasopharynx from the oropharynx. There is a large collection of lymphoid tissue (the pharyngeal tonsil) in the mucosa covering the roof of the nasopharynx. Enlargement of this tonsil, known then as adenoids, can occlude the nasopharynx so that breathing is only possible through the oral cavity (Fig. 8.205A). The most prominent features on each lateral wall of the nasopharynx are: the pharyngeal opening of the pharyngotympanic tube, and mucosal elevations and folds covering the end of the pharyngotympanic tube and the adjacent muscles. | Anatomy_Gray. The cavity of the nasopharynx is continuous below with the cavity of the oropharynx at the pharyngeal isthmus. The position of the pharyngeal isthmus is marked on the pharyngeal wall by a mucosal fold caused by the underlying palatopharyngeal sphincter, which is part of the superior constrictor muscle. Elevation of the soft palate and constriction of the palatopharyngeal sphincter closes the pharyngeal isthmus during swallowing and separates the nasopharynx from the oropharynx. There is a large collection of lymphoid tissue (the pharyngeal tonsil) in the mucosa covering the roof of the nasopharynx. Enlargement of this tonsil, known then as adenoids, can occlude the nasopharynx so that breathing is only possible through the oral cavity (Fig. 8.205A). The most prominent features on each lateral wall of the nasopharynx are: the pharyngeal opening of the pharyngotympanic tube, and mucosal elevations and folds covering the end of the pharyngotympanic tube and the adjacent muscles. |
Anatomy_Gray_2498 | Anatomy_Gray | The opening of the pharyngotympanic tube is posterior to and slightly above the level of the hard palate, and lateral to the top of the soft palate (Fig. 8.205A). Because the pharyngotympanic tube projects into the nasopharynx from a posterolateral direction, its posterior rim forms an elevation or bulge on the pharyngeal wall. Posterior to this tubal elevation (torus tubarius) is a deep recess (pharyngeal recess) (Fig. 8.205A). Mucosal folds related to the pharyngotympanic tube include: the small vertical salpingopharyngeal fold, which descends from the tubal elevation and overlies the salpingopharyngeus muscle, and a broad fold or elevation (torus levatorius) that appears to emerge from just under the opening of the pharyngotympanic tube, continues medially onto the upper surface of the soft palate, and overlies the levator veli palatini muscle. | Anatomy_Gray. The opening of the pharyngotympanic tube is posterior to and slightly above the level of the hard palate, and lateral to the top of the soft palate (Fig. 8.205A). Because the pharyngotympanic tube projects into the nasopharynx from a posterolateral direction, its posterior rim forms an elevation or bulge on the pharyngeal wall. Posterior to this tubal elevation (torus tubarius) is a deep recess (pharyngeal recess) (Fig. 8.205A). Mucosal folds related to the pharyngotympanic tube include: the small vertical salpingopharyngeal fold, which descends from the tubal elevation and overlies the salpingopharyngeus muscle, and a broad fold or elevation (torus levatorius) that appears to emerge from just under the opening of the pharyngotympanic tube, continues medially onto the upper surface of the soft palate, and overlies the levator veli palatini muscle. |
Anatomy_Gray_2499 | Anatomy_Gray | The oropharynx is posterior to the oral cavity, inferior to the level of the soft palate, and superior to the upper margin of the epiglottis (Fig. 8.205). The palatoglossal folds (arches), one on each side, that cover the palatoglossal muscles, mark the boundary between the oral cavity and the oropharynx. The arched opening between the two folds is the oropharyngeal isthmus. Just posterior and medial to these folds are another pair of folds (arches), the palatopharyngeal folds, one on each side, that overlie the palatopharyngeus muscles. | Anatomy_Gray. The oropharynx is posterior to the oral cavity, inferior to the level of the soft palate, and superior to the upper margin of the epiglottis (Fig. 8.205). The palatoglossal folds (arches), one on each side, that cover the palatoglossal muscles, mark the boundary between the oral cavity and the oropharynx. The arched opening between the two folds is the oropharyngeal isthmus. Just posterior and medial to these folds are another pair of folds (arches), the palatopharyngeal folds, one on each side, that overlie the palatopharyngeus muscles. |
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