Carotid, Submandibular and Submental Triangles of the Neck

Gross Anatomy

Carotid, Submandibular and Submental Triangles of the Neck


Anatomy Tables for Today's Topic


Bones and Cartilages of the Neck
Muscles
Nerves
Arteries
Veins
Topographic Anatomy
Lymphatics
Viscera of the Neck


Bones and Cartilages of the Neck

Bone/Cartilage Structure Description Notes
cricoid cartilage the inferior & posterior cartilage of the larynx; it forms a complete cartilaginous ring; its arch projects anteriorly and its lamina is broad and flat posteriorly connected: above to the thyroid cartilage via the inferior horn of the thyroid cartilage, to the conus elasticus, to the arytenoid cartilages which sit atop the lamina; connected below to the first tracheal ring via the cricotracheal ligament
hyoid a "U"-shaped bone consisting of several parts: body, 2 greater horns, 2 lesser horns the hyoid bone ossifies completely in middle life; the body articulates with the greater horns via cartilage and with the lesser horns via fibrous joints prior to ossification; an important site for muscle attachments (suprahyoid and infrahyoid muscle groups)
body the middle portion of the "U"-shaped bone the body of the hyoid bone articulates with the greater horns posteriorly
greater horn (cornu) posteriorly directed limbs of the "U"-shaped bone each greater horn articulates with the body and lesser horns anteriorly; origin of middle pharyngeal constrictor m. and hyoglossus m.
lesser horn (cornu) articulates with the greater horn at its junction with the body the inferior end of the stylohyoid ligament attaches to the lesser horn
thyroid cartilage the large anterior cartilage of the larynx; it has several parts: laminae (2), superior horns (2), inferior horns (2), oblique line, superior thyroid notch, connected above to the hyoid bone via the thyrohyoid membrane; connected below to the cricoid cartilage via the inferior horn of the thyroid cartilage; connected posteriorly: to the arytenoid cartilage via the vocal ligament and thyroarytenoid m., to the epiglottic cartilage via the thyroepiglottic ligament; it tilts anteriorly to increase the length of the vocal ligament and raise the pitch of the voice
lamina a broad flat plate of cartilage forming one side of the thyroid cartilage; two laminae fuse anteriorly in the midline to form the thyroid cartilage the laryngeal prominence is the line of fusion of the two laminae; each lamina is connected superiorly to the hyoid bone by the thyrohyoid membrane
superior horn the rounded, superior projection of the posterior border of the thyroid lamina it is connected superiorly to the greater horn of the hyoid bone by the lateral thyrohyoid ligament
inferior horn the rounded, inferior projection of the posterior border of the thyroid lamina it is connected inferiorly to the cricoid cartilage by the cricothyroid articulation (a synovial joint)
oblique line ridge which 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 known to the lay person as the "Adam's apple"; the laryngeal prominence is a secondary sexual characteristic - in postpuberal males the angle of the laryngeal prominence is approximately 90¡ and in females the angle is approximately 120¡
superior thyroid notch the notch at the superior end of the laryngeal prominence it is connected to the hyoid bone by the median thyrohyoid ligament

Muscles

Muscle Origin Insertion Action Innervation Artery Notes
digastric anterior belly: digastric fossa of the mandible; posterior belly: mastoid notch of the temporal bone body of the hyoid via a fibrous loop over an intermediate tendon elevates the hyoid bone; depresses the mandible anterior belly: mylohyoid nerve, from the mandibular division of the trigeminal nerve (V); posterior belly: facial nerve (VII) anterior belly: submental a.; posterior belly: occipital a. the digastric m. forms two sides of the submandibular triangle; it is formed from mesenchyme derived from the first two pharyngeal arches, hence its dual innervation
mylohyoid mylohyoid line of mandible midline raphe and body of the hyoid bone elevates the hyoid bone and the tongue; depresses the mandible mylohyoid nerve from the inferior alveolar nerve, a branch of the mandibular division of the trigeminal nerve (V) mylohyoid branch of the inferior alveolar a. the nerve to mylohyoid also innervates the anterior belly of digastric m.; both muscles are derivatives of the first pharygneal arch
omohyoid inferior belly: upper border of the scapula medial to the scapular notch; superior belly: intermediate tendon inferior belly: intermediate tendon; superior belly: lower border of the hyoid bone lateral to the sternohyoid insertion depresses/stabilizes the hyoid bone ansa cervicalis transverse cervical a. the intermediate tendon of omohyoid is tethered to the clavicle by a fascial sling
platysma fascia overlying the pectoralis major and deltoid muscles inferior border of the mandible and skin of lower face draws the corners of the mouth down; it aids in depression of the mandible cervical branch of the facial nerve (VII) facial a. platysma is derived from the mesenchyme of the second pharyngeal arch
sternocleidomastoid sternal head: anterior surface of the manubrium; clavicular head: medial 1/3rd of the clavicle mastoid process and lateral 1/2 of the superior nuchal line draws the mastoid process down toward the same side which causes the chin to turn up toward the opposite side; acting together, the muscles of the two sides flex the neck spinal accessory nerve (XI), with sensory supply from C2 & C3 (for proprioception) sternocleidomastoid branch of the occipital a. carotid sheath structures lie deep to it
stylohyoid posterior side of the styloid process splits around the intermediate tendon of the digastric m. to insert on the body of the hyoid bone elevates and retracts the hyoid bone facial nerve (VII) ascending pharyngeal a. facial nerve innervates both the stylohyoid m. and the posterior belly of the digastric m. shortly after exiting from the stylomastoid foramen

Nerves

Nerve Source Branches Motor Sensory Notes
accessory cranial root: medulla - nucleus ambiguus; spinal root: spinal nucleus of the upper cervical spinal cord no named branches GSE: sternocleidomastoid and trapezius mm. none also known as: CN XI, 11th cranial nerve; spinal root enters cranial cavity by passing through the foramen magnum; exits skull by passing through the jugular foramen; accessory n. is motor only; the subtrapezial plexus of nerves receives proprioceptive fibers: for the sternocleidomastoid m. from the ventral primary rami of spinal nn. C2 and C3 - for trapezius via ventral primary rami of C3 and C4
ansa cervicalis superior root (C1 and C2) and inferior root (C2 and C3) of the ansa cervicalis to infrahyoid muscles omohyoid m., sternohyoid m., sternothyroid m., thyrohyoid m., geniohyoid m. none superior and inferior roots of the ansa cervicalis are also known as the anterior and posterior roots
cardiac, sympathetic cervical sympathetic trunk no named branches heart (sympathetic: increases rate and force of contraction, parasympathetic: decreases rate and force of contraction); bronchial tree & lungs via pulmonary plexus heart, bronchial tree and lungs cervical sympathetic trunk usually gives 3 cervical cardiac brs. l (superior, middle and inferior) to the cardiac plexus
cardiac, vagal vagus n. (X) no named branches heart (parasympathetic: decreases rate and force of contraction; sympathetic: increases rate and force of contraction); bronchial tree and lungs via pulmonary plexus heart, bronchial tree and lungs vagus n. has 2 cervical cardiac brs. (superior and inferior) and 1 or more thoracic cardiac brs.
carotid plexus, external superior cervical ganglion of the sympathetic trunk, via the external carotid n. distributes along the brs. of the external carotid artery vascular smooth muscle, arrector pili muscles, sweat glands of face & upper neck none postganglionic sympathetic nerve fibers use arteries as roadways to enter the head and neck
carotid plexus, internal superior cervical ganglion of the sympathetic trunk, via the internal carotid n. most distribute along the brs. of the internal carotid artery, although the deep petrosal n. is an exception because it runs a short course independent of an artery vascular smooth muscle of the brain, orbit, forehead, upper nasal cavity; arrector pili muscles of forehead and anterior scalp; sweat glands of the forehead; dilator pupillae m. none postganglionic sympathetic nerve fibers use arteries as roadways to enter the head and neck
cervicofacial division facial (VII) buccal br., marginal mandibular br., cervical br. muscles of facial expression of the lower part of the face; platysma m. none cervicofacial division usually forms a loop by communication with the temporofacial division of the facial n.
hypoglossal n. medulla: hypoglossal nucleus no named branches; branches of the ventral primary ramus of spinal nerve C1 are carried by this nerve and are not considered to be branches of the hypoglossal nerve intrinsic and extrinsic muscles of the tongue (except the palatoglossus m.) none also known as: CN XII, 12th cranial nerve; the hypoglossal n. exits the posterior cranial fossa by passing through the hypoglossal canal; the superior root of the ansa cervicalis travels with the hypoglossal n. for a short distance
inferior laryngeal n. recurrent laryngeal br. of the vagus n. (X) no named branches all intrinsic muscles of the larynx except the cricothyroid; those muscles are: thyroarytenoid, oblique and transverse arytenoid, posterior and lateral cricoarytenoid, aryepiglottic, thyroepiglottic, vocalis; secretomotor to the mucous membrane of the larynx below the vocal fold mucous membrane of the larynx below the vocal fold inferior laryngeal n. is the continuation of the recurrent laryngeal n., the name change occurs at the cricothyroid articulation
mylohyoid, n. to inferior alveolar n., a branch of the mandibular division of the trigeminal n. (V3) no named branches mylohyoid m., anterior belly of the digastric m. none n. to mylohyoid arises near the lingula of the mandible; course within the mylohyoid groove of the mandible
recurrent laryngeal n. vagus n. (X) esophageal brs., tracheal brs., cardiac brs., pharyngeal brs., inferior laryngeal n. upper esophagus, lower pharynx, laryngeal mm. (except cricopharyngeus); smooth muscle of the trachea; secretomotor to mucosal glands in the upper esophagus, lower pharynx, larynx below the vocal fold, trachea; cardiac muscle of the heart (slows heart rate, decreases force of contraction) upper esophagus, lower pharynx, larynx below the vocal folds, GVA from heart right recurrent laryngeal n. loops posteriorly around the right subclavian a.; left recurrent laryngeal n. loops posteriorly around the aortic arch and ligamentum arteriosum; the inferior laryngeal br. supplies all intrinsic muscles of the larynx EXCEPT the cricothyroid m.
superior laryngeal 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
superior laryngeal n. vagus n. (X) internal br., external br. cricothyroid m., inferior pharyngeal constrictor m.; secretomotor to mucosal glands of the larynx above the vocal folds mucous membrane of the larynx above the vocal folds external br. supplies the cricothyroid m.; all other intrinsic muscles of the larynx are supplied by the recurrent laryngeal n.
sympathetic chain ganglia, cervical preganglionic sympathetic fibers arrive via white rami communicantes of ventral primary rami of spinal nerves T1-T5 postganglionic sympathetic depart via gray rami communicans to cervical spinal nn.; internal and external carotid nn.; cervical cardiac brs. dilator pupillae m.; vascular smooth muscle; arrector pili muscles and sweat glands of head and neck; heart and lungs pain from viscera located parallel to the vertebral bodies in the neck; there are no white rami communicantes at cervical levels
to carotid body glossopharyngeal n. (IX) no named branches none sensory receptors in the carotid body and carotid sinus chemoreception (blood pH) in carotid body; blood pressure receptors in carotid sinus; both located near the bifurcation of the common carotid a.; the vagus n. (X) may share a role in this innervation
vagus n. medulla: dorsal motor nucleus (GVE preganglionic parasympathetic); inferior ganglion (GVA); nucleus ambiguus (SVE); superior ganglion (GSA); inferior ganglion(SVA) auricular br., pharyngeal br., superior laryngeal, superior and inferior cervical cardiac brs., recurrent laryngeal n., thoracic cardiac brs., brs. to the pulmonary plexus, brs. to the esophageal plexus, anterior and posterior vagal trunks SVE: intrinsic muscles of the larynx, pharynx (except stylopharyngeus), and palate (except tensor veli palatini); GVE: smooth muscle of the respiratory tree & gut (proximal to the left colic flexure), heart; secretomotor: mucous glands of the larynx, respiratory tree, pharynx and gut; secretomotor to digestive glands GSA: skin of the external auditory meatus; GVA: viscera of head, neck, thorax & abdomen proximal to the left colic flexure; SVA: taste from the epiglottis also known as: CN X, 10th cranial nerve; the vagus n. passes through the jugular foramen to exit the posterior cranial fossa; vagus means "wanderer" in reference to its extensive distribution to the body cavities

Arteries

Artery Source Branches Supply to Notes
ascending pharyngeal external carotid a. pharyngeal brs., inferior tympanic a., posterior meningeal a. pharynx, meninges ascending pharyngeal a. arises from the medial side of the external carotid a. close to the birfurcation
common carotid brachiocephalic trunk (right), aortic arch (left) external carotid a., internal carotid a. most of the head and upper neck common carotid a. bifurcates at the level of the superior border of the thyroid cartilage; the internal carotid a. and the external carotid a. are its terminal brs.; the carotid sinus and carotid body are located at the bifurcation
external carotid common carotid superior thyroid a., ascending pharyngeal a., lingual a., facial a., occipital a., posterior auricular a., maxillary a., superficial temporal a. upper neck, face and scalp external carotid a. is the primary blood supply to the face and superficial head; the maxillary a. and superficial temporal a. are its terminal branches
facial external carotid a. ascending palatine a., tonsilar br., submental a., superior labial a., inferior labial a., lateral nasal a., angular a. lower part of the palatine tonsil, submandibular gland, facial muscles and fascia the angular branch of the facial a. anastomoses with the ophthalmic a.
inferior laryngeal inferior thyroid a. no named branches internal part of the inferior larynx inferior laryngeal a. accompanies the inferior laryngeal n.
inferior thyroid thyrocervical trunk ascending cervical a., inferior laryngeal a., esophageal brs., tracheal brs., glandular brs. thyroid gland, lower larynx, upper trachea, upper esophagus, deep neck muscles inferior thyroid a. gives rise to the ascending cervical a. as it arches medially
internal carotid common carotid a. none in the neck; in the head: ophthalmic a., posterior communicating a., anterior cerebral a., middle cerebral a. brain; eye and orbit; forehead internal carotid a. is the primary blood supply to the brain; it anastomoses with the vertebral aa. and the contralateral internal carotid a. in the cerebral arterial circle (of Willis); anterior and middle cerebral aa. are the terminal brs. of the internal carotid a.
lingual external carotid a. suprahyoid br., dorsal lingual brs., deep lingual a., sublingual a. tongue, suprahyoid muscles, palatine tonsil lingual a. is the 2nd branch off of the anterior side of the external carotid a.; it may arise in common with the facial a.
occipital external carotid a. sternocleidomastoid brs., auricular br., mastoid br., descending br., occipital brs. lateral neck, posterior neck, posterior scalp occipital a. anastomoses with the deep cervical a.; it courses with the greater occipital nerve on the posterior surface of the head
posterior auricular external carotid a. stylomastoid br., auricular br., occipital br. part of the external ear, scalp and deeper structures posterior to the ear posterior auricular and greater occipital share their region of distribution
submental facial a. no named branches muscles, skin and fascia under the chin; submandibular gland submental a. supplies the submandibular gland and the mylohyoid m. in addition to the skin and superficial fascia
superior laryngeal superior thyroid a. no named branches internal aspect of the superior larynx superior laryngeal a. penetrates the thyrohyoid membrane in company with the internal br. of the superior laryngeal n.
superior thyroid external carotid a. infrahyoid br., sternocleidomastoid br., superior laryngeal a., cricothyroid br., glandular brs. thyroid gland, upper part of the larynx, infrahyoid mm., sternocleidomastoid m. superior thyroid a. is usually the first branch of the external carotid a.
thyroidea ima brachiocephalic a. or aortic arch no named branches isthmus of the thyroid gland, upper trachea thyroidea ima a. is present in 10% of individuals; it is clinically significant because it is a midline artery in the region of tracheostomy; ima means "lowest"

Veins

Vein Tributaries Drains Into Regions Drained Notes
anterior jugular v. submental v, communicating v. external jugular v. superficial parts of the anterior neck anterior jugular v. is valveless
common facial v. formed by the union of the anterior division of the retromandibular v. and the facial v. internal jugular v. face and anterior scalp common facial v. may receive drainage from the lingual v.
external jugular v. formed by the joining of the retromandibular and posterior auricular vv.; tributaries: posterior external jugular v., transverse cervical v., suprascapular v., anterior jugular v. subclavian v. head & neck, shoulder external jugular v. contains valves that may not be fully functional
inferior thyroid v. numerous tributaries from the thyroid gland, esophageal v, tracheal v., inferior laryngeal v. left and right brachiocephalic vv. inferior part of the thyroid gland inferior thyroid vv. descend on the anterior surface of the trachea
internal jugular v. formed at the base of the skull where the sigmoid sinus ends; tributaries: pharyngeal vv.; lingual v., common facial v., sternocleidomastoid v., superior thyroid v, middle thyroid v. brachiocephalic v. brain, cranial cavity, skull, face, viscera of the neck internal jugular is the largest vein of the nead and neck
middle thyroid v. numerous tributaries from the thyroid gland internal jugular v. lateral aspect of the thyroid gland middle thyroid v. crosses superficial to the common carotid a.
posterior auricular v. small veins of the subcutaneous tissues behind the ear, stylomastoid v. it unites with the posterior division of the retromandibular v. to form the external jugular region behind the ear posterior auricular v. communicates with the occipital v. behind the ear
retromandibular v. formed by the union of the superficial temporal v. and maxillary v. anterior and posterior divisions of the retromandibular v. side of the head and scalp; deep face retromandibular v. is contained within the parotid gland; anterior division unites with the facial v. to form the common facial v.; posterior division unites with the posterior auricular v. to form the external jugular v.
superior thyroid v. sternocleidomastoid v., superior laryngeal v., infrahyoid v., cricothyroid v. internal jugular v. superior portion of the thyroid gland and surrounding structures superior thyroid v. is the only thyroid v. to accompany an artery; it crosses superficial to the common carotid a.
thyroidea ima v. formed by a high union of the right and left inferior thyroid vv. left brachiocephalic vein inferior part of the thyroid gland an occasional branch; a midline structure which is in danger during tracheostomy

Topographic Anatomy

Structure/Space Description/Boundaries Significance
anterior cervical triangle boundaries: medial - midline; lateral - anterior border of the sternocleidomastoid m.; superior - lower border of the mandible anterior cervical triangle may be subdivided into the carotid triangle and the muscular triangle
carotid triangle boundaries: anterior - superior belly of the omohyoid m.; posterior - sternocleidomastoid m.; superior - posterior belly of the digastric m.; the carotid artery branches here
anterior cervical triangle boundaries: medial - midline; lateral - anterior border of the sternocleidomastoid m.; superior - lower border of the mandible anterior cervical triangle may be subdivided into the carotid triangle and the muscular triangle
muscular triangle boundaries: medial - midline; superior - body of the hyoid bone; superolateral - superior belly of the omohyoid m.; inferolateral - sternocleidomastoid m. muscular triangle contains the strap muscles of the neck; larynx and thyroid gland lie deep to the strap muscles
submandibular triangle boundaries: anterior - anterior belly of the digastric m.; posterior - posterior belly of the digastric m.; superior - lower border of mandible submandibular triangle contains the submandibular gland
submental triangle boundaries: lateral - anterior belly of the digastric m.; medial - midline; inferior - body of the hyoid bone submental triangle contains the submental a. and v.

Lymphatics

Structure Location Afferents from Efferents to Regions drained Notes
deep cervical nodes in and around carotid sheath posterior and lateral to the internal jugular v. lymphatic vessels and numerous node groups from the head and neck jugular trunk head and neck superior and inferior subdivisions of deep cervical nodes are delineated by the crossing of the omohyoid m.
jugular lymphatic trunk carotid sheath in root of neck deep cervical nodes left: thoracic duct near its termination; right: right lymphatic duct or junction of right subclavian and right internal jugular vv. head & neck jugular trunk carries most of the lymph from the head and neck
jugular nodes, anterior along the anterior jugular vein lymphatic vessels from the anterior inferior part of the neck inferior deep cervical nodes skin and mm. of the anterior infrahyoid region of the neck anterior jugular nodes are located between the superficial layer of deep cervical fascia and the infrahyoid mm.
jugular nodes, external along the external jugular v. lymphatic vessels from the side of the head superior deep cervical nodes inferior part of the ear and the parotid region there are one or two nodes in this group
jugulodigastric node anterolateral to internal jugular v. where it is crossed by posterior belly of the digastric superior deep cervical nodes inferior deep cervical nodes oral cavity, tongue, palatine tonsil a member of the superior deep cervical node group; important node to palpate during physical exam
juguloomohyoid node lateral to internal jugular v. where it is crossed by superior belly of omohyoid superior deep cervical nodes inferior deep cervical nodes submental region and tip of tongue; head & neck above this level an important node to examine in cases of oral cancer caused by use of tobacco products
juxtavisceral nodes adjacent to the cervical viscera cervical viscera superior deep cervical nodes, inferior deep cervical nodes esophagus, larynx, trachea and thyroid gland four groups of juxtavisceral nodes are recognized: infrahyoid, prelaryngeal, pretracheal and paratracheal
submental nodes under the mandible on the mylohyoid m. lymphatic vessels from the lower face and chin submandibular nodes, juguloomohyoid node tip of the tongue, lower lip, floor of the mouth, chin, gums and lower incisor teeth submental nodes are important nodes to examine in cases of oral cancer caused by the use of tobacco products
superficial cervical nodes 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

Viscera of the Neck

Organ Location/Description Notes
esophagus the portion of the gastrointestinal tract between the pharynx and the stomach connects: superiorly with laryngopharynx at lower border of cricoid cartilage; inferiorly it passes through diaphragm at the T10 vertebral level to reach the stomach; the upper 1/3 is skeletal muscle innervated by the recurrent laryngeal, the lower 2/3rds is smooth muscle innervated by the vagus nn. via the esophageal plexus
larynx located anterior to the laryngopharynx at level of C4-6 vertebrae composed of: thyroid, cricoid, epiglottic, arytenoid, cuneiform & corniculate cartilages; contains the vocal ligaments; controls the airway
parathyroid glands four small endocrine glands located on the posterior surface of the lateral lobes of the thyroid gland two pair of glands that develop from the 3rd and 4th pharyngeal pouches; they produce parathormone which is important in regulating serum calcium levels
pharynx the space posterior to the nasal cavity, oral cavity and larynx divided into 3 parts: nasopharynx, oropharynx and laryngopharynx; the airway and the pathway of ingested foods and liquids cross at this location
thyroid gland a large endocrine bland that lies anterolateral to the lower part of the larynx and upper trachea thyroid gland consists of two lateral lobes joined across the midline by the isthmus; it may have a pyramidal lobe extending superiorly near midline which is a remnant of development that marks its route of migration from a primordium that originates at the foramen cecum or the tongue; thyroid gland is supplied by superior and inferior thyroid aa.; it produces thyroxin
thyroid isthmus constricted midline connection between the lateral lobes of the thyroid gland thyroid isthmus lies anterior to tracheal rings 2-4
trachea main airway that lies anterior to the esophagus trachea extends from vertebral level C6 to the level of the T4/5 intervertebral disc; superiorly it is connected to the cricoid cartilage via the cricotracheal ligament; it bifurcates into two primary bronchi

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Some of the material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest and Jaye Schlesinger
Published by ILOC, Inc., New York. Copyright 1995.

Content of these tables has been edited for use in this course by Patrick W. Tank, Ph.D.
Copyright 2005, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences.

Unauthorized use is prohibited.