Anatomy Tables - Anterior Triangle of the Neck

Osteology

BoneStructureDescription
mandible (N15, TG7-04A) mental protuberanceforms bone of chin anteriorly
hyoid (TG7-01, TG7-09)

bodyarticulates 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
laminatwo 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 linedescends diagonally from superior to inferior on the lateral surface of the thyroid lamina; a line of muscle attachment
laryngeal prominencethe line of fusion of the thyroid laminae

Muscles

MuscleOriginInsertionActionInnervationNotesImage
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 musclesinferior border of mandible and skin of lower facedraws corners of mouth down; aids in depression of the mandiblefacial nerve (VII), cervical branch(Greek, platysma = flat plate)
digastric (TG7-33) anterior belly: digastric fossa of mandible; posterior belly: mastoid notch of temporal bonebody of hyoid via fibrous loop over intermediate tendonelevates hyoid; depresses mandibleanterior 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 processsplits around intermediate tendon of digastric to insert on the body of the hyoid boneelevates and retracts hyoidfacial 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 mandiblemidline raphe and body of hyoid boneelevates hyoid bone and tongue; depresses mandiblemylohyoid 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 tendoninferior belly: intermediate tendon; superior belly: lower border of hyoid lateral to sternohyoid insertiondepresses/stabilizes hyoid boneansa cervicalisthe 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 claviclelower border of hyoid bone, medial to omohyoid insertiondepresses/stabilizes hyoid boneansa cervicalissternohyoid overlies sternothyroid and thyrohyoid
sternothyroid (TG7-12, TG7-13)posterior surface of manubrium below sternohyoid originoblique line of thyroid cartilagedepresses/stabilizes thyroid cartilage of larynxansa cervicalissternothyroid lies deep to sternohyoid
thyrohyoid (TG7-12, TG7-13)oblique line of thyroid cartilagelower border of hyoid boneelevates larynx; depresses/stabilizes hyoid boneC1&2 fibers running with hypoglossal nerve that leave XII anterior to the superior root of ansa cervicalisthyrohyoid lies deep to the sternohyoid
sternocleidomastoid (TG7-12, TG7-13)sternal head: anterior surface of manubrium; clavicular head: medial 1/3rd of claviclemastoid process and lateral 1/2 of superior nuchal linedraws mastoid process down to same side; turns chin up toward opposite sidespinal accessory nerve (XI), with sensory supply from C2 & C3 (for proprioception)carotid sheath structures lie deep to it

Nerves

NerveSourceBranchesMotorSensoryNotes
cervical plexus (TG7-17)ventral primary rami of C1-C4 spinal nervesbrs. 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, diaphragmskin of neck anterolaterally; skin of ear & behind earclose 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 eararises from a ventral primary ramus
ansa cervicalis (N36, N135, TG7-12, TG7-13) superior root (C1&C2) & inferior root (C2&C3) of ansa cervicalisto infrahyoid musclesomohyoid, sternohyoid, sternothyroid, thyrohyoid, geniohyoidsuperior & 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 cordcranial root joins vagus; spinal root ascends through foramen magnumGSE: 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 nucleusbranches of C1 carried by this nerve are not considered to be branches of the hypoglossal nerveintrinsic 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 ganglionauricular br., pharyngeal br., superior laryngeal, superior & inferior cervical cardiac brs., recurrent laryngeal, thoracic cardiac brs., brs. to pulmonary plexus, esophageal plexus, anterior & posterior vagal trunksSVE: 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 glandsGSA: skin of external auditory meatus; GVA: viscera of head, neck, thorax & abdomen proximal to splenic flexure; SVA: taste to epiglottisalso 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-T5postganglionic 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 & lungspain from visceralocated parallel & lateral to vertebral bodies in neck; there are no white rami communicans at cervical levels
cervicofacial divisionfacial (VII)buccal, marginal mandibular, cervicalmuscles of lower part of face, platysmausually 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 heartright 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 foldsmucous lining of larynx above vocal foldsexternal 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 foldmucous lining of larynx below vocal foldcontinuous with recurrent laryngeal at inferior border of cricopharyngeus

Arteries

ArterySourceBranchesSupplyNotes
common carotid (N69, N136, TG7-19, TG7-71)brachiocephalic trunk (right), aortic arch (left)external & internal carotid (terminal brs.)most of head & upper neckcommon 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 carotidnone in the neck; in the head: ophthalmic, post. communicating, ant. & middle cerebral (terminal brs.)brain, eye, foreheadprimary blood supply to the brain; anastomoses with vertebral aa.
external carotid (N69, N136, TG7-19, TG7-71)common carotidsuperior thyroid, ascending pharyngeal, lingual, facial, occipital, post. auricular, maxillary & superficial temporal (terminal brs.)upper neck, face & scalpprimary blood supply to face & superficial head
superior thyroid (N74, N75, N76, TG7-13, TG7-14) external carotidinfrahyoid 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 trunkascending cervical, inferior laryngeal, esophageal brs., tracheal brs., glandular brs.thyroid gland, lower larynx, upper trachea & esophagus, neck muscles
thyroidea imabrachiocephalic a. or aortic archno named branchesisthmus of thyroid gland, upper tracheapresent 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 thyroidupper larynx internally

Veins

VeinTributariesDrains IntoRegion Drained Notes
anterior jugular (N31,N74, TG7-11)submental, communicatingexternal jugularanterior 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 jugularsubclavian 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 necklargest 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 imaleft brachiocephalic veininferior 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/SpaceBoundaries/DescriptionSignificance
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

StructureLocationAfferents fromEfferents toRegions drainedNotes
nodes, deep cervical (N72, TG7-74) in and around carotid sheathlymphatic vessels from head & neckjugular trunkhead & necksuperior and inferior subdivisions are delineated by the crossing of the omohyoid m.
nodes, superficial cervicalin superficial fascia and along superficial vessels of the head & necklymphatic vessels from superficial structures in head & neckvaries by group; ultimate destination is the jugular trunkhead & neckseveral groups are designated by location: occipital, retroauricular, anterior auricular, superficial parotid, facial, submental, submandibular, external jugular, anterior jugular
submental nodesunder mandible on mylohyoid m.juguloomohyoid node, submandibular nodestip of tongue, lower lip, floor of mouthimportant nodes to examine in cases of oral cancer caused by use of tobacco products

Viscera

OrganLocation/DescriptionNotes
thyroid gland (N74, TG7-13, TG7-14) lies anterolateral to lower part of larynx & upper tracheatwo 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 thyroidlies anterior to tracheal rings 2-4
parathyroid glands (N75, TG7-14) two pair, located posteriorly on lateral lobes of thyroid gland
esophagusconnects 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 laryngeallower 2/3rds is smooth muscle innervated by vagus via esophageal plexus
larynxlocated anterior to laryngopharynx at level of C4-6 vert.; composed of thyroid, cricoid, epiglottic, arytenoid, cuneiform & corniculate cartilagescontains vocal ligaments
pharynxconnects nasal & oral cavities with larynx & esophagus divided into 3 parts: nasopharynx, oropharynx & laryngopharynx
trachealies anterior to esophagus; extends from vertebral level C6 to T4/5 disc; connects above to cricoid via cricotracheal ligamentbifurcation into primary bronchi is marked by carina

Fascia

FasciaLocation/DescriptionNotes
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 thoraxcloses & 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 neckcovers 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

Clinical Terms

Term Definition
goiter enlargement of the thyroid gland. A goiter is not cancerous. A goiter can be associated with normal, elevated (hyperthyroidism) or decreased (hypothyroidism) thyroid hormone levels in the blood.
tracheostomy The surgical creation of an artificial airway in the trachea (windpipe) on the anterior surface of the neck.
cricothyrotomy an emergency procedure where a cut or passageway is made in the cricothyroid membrane.
thyroidectomy surgery to remove part or all of the thyroid gland. This might be done to remove a tumor or treat hyperthyroidism or goiter (enlarged thyroid gland). The goal of surgery in hyperthyroidism is to remove just enough thyroid gland so that a normal amount of thyroid hormone is produced. If too much thyroid is removed, the patient will produce too little thyroid hormone (hypothyroidism) and need treatment to return the thyroid status to normal (euthyroid). The complications of surgery can include vocal cord paralysis (if the recurrent laryngeal n. is cut) and accidental removal of the parathyroid glands (located behind the thyroid gland), resulting in low calcium levels (the parathyroid glands regulate calcium).
thyroglossal duct cyst a thyroglossal cyst is a fluid-filled sac that is present at birth and located in the midline of the neck. A thyroglossal cyst is a result of incomplete closure of a segment of a tube-like structure (the thyroglossal duct) that is present, and normally closes, as the embryo develops. A thyroglossal cyst is also called a thyrolingual cyst.
torticollis a wry neck, a contracted state of the cervical muscles, producing twisting of the neck and an unnatural position of the head. (Latin, tortus = twisted + collum = neck)

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.