 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Anatomy Tables - Anterior Triangle of the Neck
|
|||||||||||||
|
|
||||||||||||
|
|||||||||||||
Anatomy Tables - Anterior Triangle of the Neck |
|||||||||||||
|
|||||||||||||
Osteology | ||
|---|---|---|
| Bone | Structure | Description |
| mandible (N15, TG7-04A) | mental protuberance | forms bone of chin anteriorly |
| hyoid (TG7-01, TG7-09) | body | articulates with greater horns via cartilage and lesser horn via fibrous joint (Greek, hyoid = U-shaped) |
| greater horns (cornua) | articulate with body and lesser horns anteriorly; origin of middle pharyngeal constrictor and hyoglossus | |
| lesser horns (cornua) | articulate at junction of body with greater horns; inferior attachment of stylohyoid ligament | |
| cricoid cartilage (TG7-01, TG7-09) | inferior & posterior cart. of larynx; arch is narrow anteriorly, lamina is broad posteriorly; connected: above to thyroid cart. via inferior horn of thyroid cart., above to conus elasticus, above (on lamina) to arytenoid carts., below to 1st tracheal ring via cricotracheal lig. (Greek, cricoid = a ring form) | |
| occipital (TG7-05,TG7-06) | the bone forming the posterior surface of the skull; it articulates superolaterally with the parietal bones through the lambdoid suture, anteroinferiorly with the temporal bone and anteriorly with the body of the sphenoid bone | |
| sternum (N1, N185, TG4-04) | jugular notch | located in the manubrium of the sternum in the fossa between the sternal heads of the SCM, the suprasternal space and jugular venous arch are located superior to the jugular notch |
| temporal (TG7-04, TG7-06, TG7-07) | the bone forming the lateral side of the skull, temporal refers to the passage of time, which is marked by the appearance of gray hair on the sides of the head | |
| mastoid process | the process located posteroinferior to the external acoustic meatus; it projects inferiorly from the junction of the petrous and squamous parts of the temporal bone; it contains the mastoid air cells that open into tympanic cavity through the mastoid antrum (Greek, mastoid = resembles the breast/nipple-like structure) | |
| thyroid cartilage (TG7-01, TG7-09, TG7-25) | anterior cart. of larynx; connected: above to hyoid bone via thyrohyoid membrane, below to cricoid cart. via inferior horn, posteriorly to arytenoid cart. via vocal lig. & thyroarytenoid m., posteriorly to epiglottic cart. via thyroepiglottic lig.; tilts forward to increase tension on vocal lig. & increase pitch of voice | |
| lamina | two laminae fuse anteriorly in the midline to form the thyroid cartilage; laryngeal prominence is the line of fusion of the laminae (Latin, lamina = a thin plate) | |
| oblique line | descends diagonally from superior to inferior on the lateral surface of the thyroid lamina; a line of muscle attachment | |
| laryngeal prominence | the line of fusion of the thyroid laminae |
Muscles | ||||||
|---|---|---|---|---|---|---|
| Muscle | Origin | Insertion | Action | Innervation | Notes | Image |
| cricothyroid (TG7-26) | arch of the cricoid cartilage | inferior border of the thyroid cartilage | draws the thyroid cartilage forward, lengthening the vocal ligaments | external branch of superior laryngeal nerve, a branch of the vagus nerve (X) | this is the only intrinsic muscle of the larynx that is not supplied by the recurrent laryngeal n.; ALL other laryngeal muscles are innervated by recurrent laryngeal nerve, via its inferior laryngeal branch | ) |
| platysma (TG7-29) | fascia overlying the pectoralis major and deltoid muscles | inferior border of mandible and skin of lower face | draws corners of mouth down; aids in depression of the mandible | facial nerve (VII), cervical branch | (Greek, platysma = flat plate) | ) |
| digastric (TG7-33) | anterior belly: digastric fossa of mandible; posterior belly: mastoid notch of temporal bone | body of hyoid via fibrous loop over intermediate tendon | elevates hyoid; depresses mandible | anterior belly: mylohyoid nerve, from mandibular division of trigeminal nerve (V); posterior belly: facial nerve (VII) | forms two sides of the submandibular triangle | ) |
| stylohyoid (TG7-21, TG7-34) | posterior border of styloid process | splits around intermediate tendon of digastric to insert on the body of the hyoid bone | elevates and retracts hyoid | facial nerve (VII) | facial nerve innervates both stylohyoid and posterior belly of digastric shortly after exiting from the stylomastoid foramen | ) |
| mylohyoid (TG7-21,TG7-33) | mylohyoid line of mandible | midline raphe and body of hyoid bone | elevates hyoid bone and tongue; depresses mandible | mylohyoid nerve from inferior alveolar nerve, a branch of mandibular division of trigeminal nerve (V) | the nerve to mylohyoid also innervates anterior belly of digastric m. | ) |
| omohyoid (TG7-10, TG7-12) | inferior belly: upper border of scapula medial to scapular notch; superior belly: intermediate tendon | inferior belly: intermediate tendon; superior belly: lower border of hyoid lateral to sternohyoid insertion | depresses/stabilizes hyoid bone | ansa cervicalis | the intermediate tendon of omohyoid is tethered to the clavicle by a fascial sling | ) |
| sternohyoid (TG7-12, TG7-13) | posterior surfaces of manubrium and sternal end of clavicle | lower border of hyoid bone, medial to omohyoid insertion | depresses/stabilizes hyoid bone | ansa cervicalis | sternohyoid overlies sternothyroid and thyrohyoid | ) |
| sternothyroid (TG7-12, TG7-13) | posterior surface of manubrium below sternohyoid origin | oblique line of thyroid cartilage | depresses/stabilizes thyroid cartilage of larynx | ansa cervicalis | sternothyroid lies deep to sternohyoid | ) |
| thyrohyoid (TG7-12, TG7-13) | oblique line of thyroid cartilage | lower border of hyoid bone | elevates larynx; depresses/stabilizes hyoid bone | C1&2 fibers running with hypoglossal nerve that leave XII anterior to the superior root of ansa cervicalis | thyrohyoid lies deep to the sternohyoid | ) |
| sternocleidomastoid (TG7-12, TG7-13) | sternal head: anterior surface of manubrium; clavicular head: medial 1/3rd of clavicle | mastoid process and lateral 1/2 of superior nuchal line | draws mastoid process down to same side; turns chin up toward opposite side | spinal accessory nerve (XI), with sensory supply from C2 & C3 (for proprioception) | carotid sheath structures lie deep to it | ) |
Nerves | |||||
|---|---|---|---|---|---|
| Nerve | Source | Branches | Motor | Sensory | Notes |
| cervical plexus (TG7-17) | ventral primary rami of C1-C4 spinal nerves | brs. to: longus colli & capitis, sternocleidomastoid, trapezius, levator scapulae, scalenus medius, rectus capitis anterior & lateralis: superior & inferior root of ansa cervicalis, n. to thyrohyoid, n. to geniohyoid, lesser occipital, great auricular, transverse cervical, supraclavicular nn. (medial, intermediate & lateral), contribution to phrenic n. | longus colli & capitis, rectus capitis anterior & lateralis, infrahyoid mm., thyrohyoid, geniohyoid, diaphragm | skin of neck anterolaterally; skin of ear & behind ear | close association of supraclavicular nn. to phrenic n. results in pain from diaphragm referred to shoulder (Latin, plexus = a braid) |
| transverse cervical (N33, N184, TG1-13, TG7-14, TG7-15A, TG7-15B) | cervical plexus (C2&C3) | skin of neck anteriorly | |||
| supraclavicular, intermediate (TG7-16A, TG7-16B) | cervical plexus (C3&C4) | skin of root of neck & upper chest near mid-clavicle | |||
| supraclavicular, lateral (TG7-16A, TG7-16B) | cervical plexus (C3&C4) | skin of root of neck & upper shoulder | pain from respiratory diaphragm is referred to the shoulder | ||
| supraclavicular, medial (TG7-16A, TG7-16B) | cervical plexus (C3&C4) | skin of root of neck& upper chest anteriorly | |||
| great auricular (N24,N31,N32,N129, TG7-11, TG7-16A, TG7-16B) | cervical plexus (C2&C3) | mastoid; auricular | skin of ear & below ear | ||
| occipital, lesser (N24,N31,N32,N129, TG7-11, TG7-16A, TG7-16B) | cervical plexus (C2) | skin behind ear | arises from a ventral primary ramus | ||
| ansa cervicalis (N36, N135, TG7-12, TG7-13) | superior root (C1&C2) & inferior root (C2&C3) of ansa cervicalis | to infrahyoid muscles | omohyoid, sternohyoid, sternothyroid, thyrohyoid, geniohyoid | superior & inferior roots also known as anterior & posterior roots (Latin, ansa = handle or loop) | |
| accessory (TG7-51, TG7-52, TG7-53) | cranial root: nucleus ambiguus; spinal root: spinal nucleus of upper cervical spinal cord | cranial root joins vagus; spinal root ascends through foramen magnum | GSE: sternocleidomastoid and trapezius mm. | also known as: CN XI, 11th cranial nerve; passes through jugular foramen; accessory n. is motor only; proprioceptive fibers reach sternocleidomastoid via C2&C3 and trapezius via C3&C4 (subtrapezial plexus) | |
| hypoglossal (N32, N71, N128, TG7-13, TG7-18) | medulla: hypoglossal nucleus | branches of C1 carried by this nerve are not considered to be branches of the hypoglossal nerve | intrinsic and extrinsic muscles of the tongue (except palatoglossus m.) | also known as: CN XII, 12th cranial nerve; passes through the hypoglossal canal; superior root of ansa cervicalis travels with the hypoglossal n. | |
| vagus (N132, TG7-14) | medulla: dorsal nucleus (GVA & GVE preganglionic parasympathetic) from inferior ganglion, nucleus ambiguus (SVE); spinal trigeminal nucleus (GSA) from superior ganglion; nucleus solitarius (SVA) from inferior ganglion | auricular br., pharyngeal br., superior laryngeal, superior & inferior cervical cardiac brs., recurrent laryngeal, thoracic cardiac brs., brs. to pulmonary plexus, esophageal plexus, anterior & posterior vagal trunks | SVE: intrinsic muscles of larynx, pharynx (except stylopharyngeus), & palate (except tensor veli palatini); GVE: smooth muscle of respiratory tree & gut (proximal to splenic flexure), heart; secretomotor: mucous glands of larynx, respiratory tree, pharynx & gut, digestive glands | GSA: skin of external auditory meatus; GVA: viscera of head, neck, thorax & abdomen proximal to splenic flexure; SVA: taste to epiglottis | also known as: CN X, 10th cranial nerve; passes through jugular foramen; (Latin,vagus = wanderer, because of its wide distribution to the body cavities) |
| sympathetic chain ganglia cervical (N129, N130, TG7-15, TG7-95) | preganglionic sympathetic via ascending fibers from T1-T5 | postganglionic sympathetic via gray rami communicans to cervical spinal nn.; internal & external carotid nn.; cervical cardiac brs. | dilator pupillae m.; vascular smooth muscle; arrector pili muscles & sweat glands of head and neck; heart & lungs | pain from viscera | located parallel & lateral to vertebral bodies in neck; there are no white rami communicans at cervical levels |
| cervicofacial division | facial (VII) | buccal, marginal mandibular, cervical | muscles of lower part of face, platysma | usually forms a loop by communication anteriorly with temporofacial division | |
| recurrent laryngeal (N75, N232, TG7-14, TG7-20) | vagus (X) | esophageal brs., tracheal brs., cardiac brs., pharyngeal brs., inferior laryngeal n. | upper esophagus, lower pharynx, laryngeal ms. (except cricopharyngeus); smooth muscle of trachea; secretomotor to mucous glands in upper esophagus, lower pharynx, larynx below vocal fold, trachea; cardiac muscle of heart (slows rate, decreases force of contraction) | upper esophagus, lower pharynx, larynx below vocal folds, GVA from heart | right recurrent loops posteriorly around right subclavian a.; left recurrent loops posteriorly around aortic arch & ligamentum arteriosum; inferior laryngeal br. supplies all intrinsic muscles of the larynx EXCEPT cricothyroid m. |
| superior laryngeal (TG7-13, TG7-14, TG7-20, TG7-21) | vagus (X) | internal & external brs. | cricothyroid, inferior pharyngeal constrictor, secretomotor to mucous glands of larynx above vocal folds | mucous lining of larynx above vocal folds | external br. supplies cricothyroid m.; all other intrinsic muscles of the larynx are supplied by the recurrent laryngeal nerve |
| inferior laryngeal (TG7-28) | recurrent laryngeal br. of vagus (X) | all muscles of larynx except cricothyroid: thyroarytenoid, oblique & transverse arytenoid, posterior & lateral cricoarytenoid, aryepiglottic, thyroepiglottic, vocalis; secretomotor to mucous glands of larynx below vocal fold | mucous lining of larynx below vocal fold | continuous with recurrent laryngeal at inferior border of cricopharyngeus |
Arteries | ||||
|---|---|---|---|---|
| Artery | Source | Branches | Supply | Notes |
| common carotid (N69, N136, TG7-19, TG7-71) | brachiocephalic trunk (right), aortic arch (left) | external & internal carotid (terminal brs.) | most of head & upper neck | common carotid a. bifurcates at the level of the superior border of the thyroid cartilage; carotid sinus & body located at bifurcation |
| internal carotid (N69, N136, TG7-19, TG7-72) | common carotid | none in the neck; in the head: ophthalmic, post. communicating, ant. & middle cerebral (terminal brs.) | brain, eye, forehead | primary blood supply to the brain; anastomoses with vertebral aa. |
| external carotid (N69, N136, TG7-19, TG7-71) | common carotid | superior thyroid, ascending pharyngeal, lingual, facial, occipital, post. auricular, maxillary & superficial temporal (terminal brs.) | upper neck, face & scalp | primary blood supply to face & superficial head |
| superior thyroid (N74, N75, N76, TG7-13, TG7-14) | external carotid | infrahyoid br., sternocleidomastoid br., sup. laryngeal, cricothyroid br., ant., post. & lat. glandular brs. | thyroid gland, upper larynx, infrahyoid muscles, sternocleidomastoid | |
| inferior thyroid (N74, N75, N76, TG7-13, TG7-14) | thyrocervical trunk | ascending cervical, inferior laryngeal, esophageal brs., tracheal brs., glandular brs. | thyroid gland, lower larynx, upper trachea & esophagus, neck muscles | |
| thyroidea ima | brachiocephalic a. or aortic arch | no named branches | isthmus of thyroid gland, upper trachea | present in 10% of individuals; clinically significant because it is a midline artery in the region of tracheostomy; ima means "lowest" |
| inferior laryngeal (TG7-26) | inferior thyroid | lower larynx internally | ||
| superior laryngeal (TG7-13, TG7-14) | superior thyroid | upper larynx internally |
Veins |
|||||
|---|---|---|---|---|---|
| Vein | Tributaries | Drains Into | Region Drained | Notes | |
| anterior jugular (N31,N74, TG7-11) | submental, communicating | external jugular | anterior neck superficially | (Latin, jugulum = throat) | |
| external jugular (N31,N74, TG7-11) | formed by the union of the retromandibular & posterior auricular vv.; tributaries: posterior external jugular, transverse cervical, suprascapular, anterior jugular | subclavian v. | head & neck, shoulder | (Latin, jugulum = throat) | |
| internal jugular (N31, TG7-13) | formed by the union of the sigmoid & inferior petrosal sinuses; tributaries: pharyngeal vv.; lingual, common facial, sternocleidomastoid, superior & middle thyroid vv. | brachiocephalic v. | brain & skull, face, viscera of neck | largest vein of the head and neck (Latin, jugulum = throat) | |
| superior thyroid (N74,N75,N76, TG7-13, TG7-14) | superior laryngeal v. | internal jugular v. | superior portion of thyroid gland and surrounding structures | cross the common carotid a. | |
| middle thyroid (N74, TG7-13) | internal jugular v. | thyroid gland laterally | |||
| inferior thyroid (N74, N75, N76, TG7-13, TG7-14) | left and right brachiocephalic vv. | thyroid gland inferiorly | |||
| thyroidea ima | left brachiocephalic vein | inferior portion of thyroid gland | an occasional branch formed by the union of the left and right inferior thyroid vv.; a midline structure which is in danger during tracheostomy |
Topographic Anatomy | ||
|---|---|---|
| Structure/Space | Boundaries/Description | Significance |
| cervical triangle, anterior (N28, TG7-02A, TG7-02B) | boundaries: medial - midline; lateral - anterior border of sternocleidomastoid m.; superior - lower border of mandible | |
| cervical triangle, posterior (N28, TG7-02A, TG7-02B) | boundaries: anterior - sternocleidomastoid m.; posterior - trapezius m.; inferior - clavicle | |
| muscular triangle (N28, TG7-02A, TG7-02B) | boundaries: medial - midline; superolateral - superior belly of omohyoid m.; inferolateral - sternocleidomastoid m. | |
| submandibular triangle (N28, TG7-02A, TG7-02B) | boundaries: anterior - anterior belly of digastric m.; posterior - posterior belly of digastric m.; superior - lower border of mandible | |
| submental triangle (N28, TG7-02A, TG7-02B) | boundaries: lateral - both digastric muscles (anterior bellies); inferior - hyoid bone | |
| carotid triangle (N28, TG7-02A, TG7-02B) | boundaries: lateral - sternocleidomastoid m.; superior - posterior belly of digastric m.; anterior - superior belly of omohyoid m. | carotid artery branches here |
| omoclavicular triangle (N28, TG7-02A, TG7-02B) | boundaries: superior - inferior belly of omohyoid m.; anterior - sternocleidomastoid m.; inferior - clavicle | |
| occipital triangle (N28, TG7-02A, TG7-02B) | boundaries: anterior - sternocleidomastoid m.; posterior - trapezius m.; inferior - omohyoid m. |
Lymphatics | |||||
|---|---|---|---|---|---|
| Structure | Location | Afferents from | Efferents to | Regions drained | Notes |
| nodes, deep cervical (N72, TG7-74) | in and around carotid sheath | lymphatic vessels from head & neck | jugular trunk | head & neck | superior and inferior subdivisions are delineated by the crossing of the omohyoid m. |
| nodes, superficial cervical | in superficial fascia and along superficial vessels of the head & neck | lymphatic vessels from superficial structures in head & neck | varies by group; ultimate destination is the jugular trunk | head & neck | several groups are designated by location: occipital, retroauricular, anterior auricular, superficial parotid, facial, submental, submandibular, external jugular, anterior jugular |
| submental nodes | under mandible on mylohyoid m. | juguloomohyoid node, submandibular nodes | tip of tongue, lower lip, floor of mouth | important nodes to examine in cases of oral cancer caused by use of tobacco products |
Viscera | ||
|---|---|---|
| Organ | Location/Description | Notes |
| thyroid gland (N74, TG7-13, TG7-14) | lies anterolateral to lower part of larynx & upper trachea | two lateral lobes joined across midline by isthmus; may have pyramidal lobe extending superiorly near midline; supplied by superior & inferior thyroid aa.; produces thyroxine |
| thyroid isthmus (N74, TG7-13, TG7-14) | constricted midline connection between lateral lobes of thyroid | lies anterior to tracheal rings 2-4 |
| parathyroid glands (N75, TG7-14) | two pair, located posteriorly on lateral lobes of thyroid gland | |
| esophagus | connects superiorly with laryngopharynx at lower border of cricoid cartilage, inferiorly through diaphragm at T10 vertebral level to reach stomach; upper third is skeletal muscle innervated by recurrent laryngeal | lower 2/3rds is smooth muscle innervated by vagus via esophageal plexus |
| larynx | located anterior to laryngopharynx at level of C4-6 vert.; composed of thyroid, cricoid, epiglottic, arytenoid, cuneiform & corniculate cartilages | contains vocal ligaments |
| pharynx | connects nasal & oral cavities with larynx & esophagus | divided into 3 parts: nasopharynx, oropharynx & laryngopharynx |
| trachea | lies anterior to esophagus; extends from vertebral level C6 to T4/5 disc; connects above to cricoid via cricotracheal ligament | bifurcation into primary bronchi is marked by carina |
Fascia | ||
|---|---|---|
| Fascia | Location/Description | Notes |
| carotid sheath | fascial investment that extends from the base of the skull to the root of the neck | blends anteriorly with the investing and pretracheal layers of fascia and posteriorly with the prevertebral layer of deep cervical fascia |
| fascia, alar (TG7-10B) | anterior lamina of prevertebral fascia, attaching anteriorly to visceral fascia behind esophagus in upper thorax | closes & separates retropharyngeal space above from "danger space" below |
| fascia, buccopharyngeal (TG7-10A, TG7-10B, TG7-23B) | posterior part of visceral fascia of neck; lies behind pharynx & esophagus | |
| fascia, infrahyoid (TG7-10A, TG7-10B, ) | sheet over the midline that covers the strap muscles | deep to superficial cervical fascia, superior to pretracheal fascia |
| fascia, pharyngobasilar (TG7-19, TG7-21, TG7-23B) | submucosa of pharynx; attached to base of skull | |
| fascia, pretracheal (TG7-10A, TG7-10B, TG7-11) | anterior part of visceral fascia of neck | covers thyroid gland & larynx/trachea |
| fascia, prevertebral (N35, TG7-10A, TG7-10B) | deep fascia surrounding vertebral column and associated muscles, including scalene ms. (scalene fascia) | |
| fascia, scalene (N35, TG7-10A,TG7-10B) | part of prevertebral fascia covering scalene mm. | reinforces cervical pleura (known there as Sibson's fascia) |
| fascia, superficial layer of deep cervical (TG7-10A, TG7-10B, TG1-12) | deep fascia extending between trapezius & sternocleidomastoid in posterior triangle and between the paired sternocleidomastoid mm. in anterior triangle | |
| fascia, visceral (TG7-10B) | deep fascia enclosing the visceral structures of the neck (thyroid gland, larynx/trachea, esophagus) | anterior part also known as pretracheal fascia, posterior part also known as buccopharyngeal fascia |
|
The material presented in these tables is contained in the book: MedCharts Anatomy by Thomas R. Gest & Jaye Schlesinger Published by ILOC, Inc., New York Copyright © 1995, unauthorized use prohibited. |
The excellent editorial assistance of Dr. Pat Tank, UAMS is gratefully acknowledged. |
|
||
| Copyright© 2000 The University of Michigan. Unauthorized use prohibited. |
|
|