Anatomy Tables - Posterior Triangle of the Neck

Osteology

Bone/Cartilage Structure Description Notes
occipital (N8, 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
foramen magnum the opening in the occipital bone posterior to the basal part it transmits the spinal cord, two vertebral aa., and two spinal accessory nerves
hypoglossal canal an opening in the lateral part of the occipital bone paired; it transmits the hypoglossal nerve
occipital condyle a low, wide projection from the inferior surface of the lateral part of the occipital bone paired; it articulates with the atlas
jugular notch a notch located on the anterolateral edge of the lateral part of the occipital bone it forms the posterior margin of the jugular foramen; the temporal bone forms the anterior margin of the jugular foramen
temporal bone forming the lateral side of the skull (Latin, temporis = of time. Temporal refers the passage of time, which is marked by the appearance of gray hair on the side of the head)
petrous part (TG7-08) the hard part of the temporal bone located in the floor of the cranial cavity it contains the tympanic cavity (middle ear) and the bony labyrinth of the inner ear
carotid canal (TG7-06) a canal which courses through the petrous part of the temporal bone it transmits the internal carotid a. and the internal carotid plexus of nerves into the cranial cavity
styloid process (TG7-06) the spike of bone that projects inferiorly from the petrous part of the temporal bone it is the attachment site for the stylohyoid, styloglossus and stylopharyngeus mm. and the stylomandibular and stylohyoid ligaments
rib 1 (N186, TG4-04) the most cephalic rib it is the broadest, shortest and widest of the ribs; the scalene tubercle marks its superior surface and is an elevation between grooves for the subclavian vein & artery; the scalene tubercle is the attachment site of the scalenus anterior m.
cervical vertebrae (N18, TG1-04) the seven vertebrae of the neck cervical vertebrae have the features of the typical vertebra plus all have transverse foramina (for passage of the vertebral artery); C2-C6 have bifid spinous processes; cervical vertebrae have relatively small bodies; several cervical vertebra are named: atlas, axis, vertebra prominens

Muscles

MuscleOriginInsertionActionInnervationNotesImage
scalene, anterior (N28, N30, N32, TG7-15A, TG7-15B, TG7-17, TG7-18) anterior tubercles of transverse processes of vertebrae C3-C6scalene tubercle of first ribelevates first rib; flexes and laterally bends the neckbrachial plexus, C5-C7a muscle of inspiration; anterior scalene inserts behind the subclavian vein, and anterior to the subclavian artery and roots of the brachial plexus (Greek, skalenos = uneven, having sides of unequal length)
scalene, middle (N28, N30, N32, TG7-15A, TG7-15B, TG7-17, TG7-18)posterior tubercles of the transverse processes of vertebrae C2-C7upper surface of first rib behind subclavian arteryelevates first rib; flexes and laterally bends the neckbrachial plexus, C3-C8a muscle of respiration (inspiratory); also called scalenus medius; penetrated by the dorsal scapular n. and long thoracic n. (Greek, skalenos = uneven, having sides of unequal length)
scalene, posterior (N28, N30, N32, TG7-15A, TG7-15B, TG7-17, TG7-18)posterior tubercles of the transverse processes of vertebrae C5-C7lateral surface of second ribelevates second rib; flexes and laterally bends the neckbrachial plexus, C7-C8a muscle of respiration (inspiratory); the longest of the scalene muscles (Greek, skalenos = uneven, having sides of unequal length)
constrictor, superior pharyngeal (TG7-19) medial pterygoid plate, pterygoid hamulus, pterygomandibular raphe, mylohyoid line of mandible pharyngeal tubercle and midline pharyngeal raphe constricts the pharyngeal cavity vagus (X), via pharyngeal plexus none
constrictor, middle pharyngeal (TG7-19) lesser and greater horns of hyoid bone and inferior part of the stylohyoid ligament midline pharyngeal raphe constricts the pharyngeal cavity vagus, via pharyngeal plexus none
constrictor, inferior pharyngeal (TG7-19) oblique line of thyroid cartilage, lateral surface of cricoid cartilage midline pharyngeal raphe constricts pharyngeal cavity vagus (X), via pharyngeal plexus, with aid from superior laryngeal and recurrent laryngeal nerves most external of the three pharyngeal constructor mm.
stylopharyngeus (TG7-19) medial side of styloid process superior border of thyroid cartilage and also into the pharyngeal wall elevates the larynx glossopharyngeal nerve (IX) stylopharyngeus, the only muscle innervated by IX, is the only pharyngeal muscle NOT innervated by vagus (X) nerve

Nerves

NerveSourceBranchesMotorSensoryNotes
glossopharyngeal (TG7-19) medulla: spinal trigeminal nucleus from superior ganglion (GVA); nucleus solitarius from inferior ganglion (SVA); nucleus ambiguus (GVA); inferior salivatory nucleus (GVE preganglionic parasympathetic) tympanic nerve to tympanic plexus & lesser petrosal n., carotid sinus n., stylopharyngeus brs., pharyngeal brs. GSE: stylopharyngeus; GVE: secretomotor to parotid gland (preganglionic parasympathetic via tympanic n. to lesser petrosal n. to otic ganglion, postganglionic parasympathetic via auriculotemporal n.) GVA: carotid body & sinus, pharynx, middle ear; GSA: skin of external ear; SVA: taste from posterior 1/3rd of tongue also known as: CN IX, 9th cranial nerve; passes through jugular foramen; may penetrate the stylopharyngeus m.
hypoglossal (TG7-19) 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.
cervical plexus 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)
accessory N71, N127, TG7-18, TG7-93)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)
vagus (TG7-21) 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)
pharyngeal plexus motor contributed by the vagus n. (X); sensory contributed by the glossopharyngeal n. (IX), vasomotor contributed by the superior cervical sympathetic ganglion no named branches vagus: all muscles of the pharynx except stylopharyngeus; sympathetic: smooth muscle in the pharyngeal vasculature glossopharyngeal: mucous membrane lining the pharynx the muscles of the pharyngeal wall are skeletal m. derived from the mesenchyme of the 4th pharyngeal arch (Latin, plexus = a braid)
superior laryngeal (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
cardiac (N130, TG7-15, TG7-95) vagus (X); cervical sympathetic trunk heart (parasympathetic: decreases rate & force of contraction; sympathetic: increases rate & force of contraction); bronchial tree & lungs via pulmonary plexus heart, bronchial tree & lungs vagus has 2 (superior & inferior) cervical cardiac brs. & 1 or more thoracic br.; cervical sympathetic trunk usually gives 3 (superior, middle & inferior) cardiac brs.
to carotid body vagus (X) & glossopharyngeal (IX) chemoreception (blood pH) in carotid body; blood pressure recerptors in carotid sinus; both located near bifurcation of common carotid a.
phrenic (N30, N193, TG4-18, TG7-15)ventral primary rami of C3-C5 (cervical plexus)pericardial brs.diaphragmpericardium; mediastinal, diaphragmatic & costal pleuracrosses the anterior surface of the anterior scalene m. (Greek, phrenic = diaphragm)
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
carotid plexus, external (N130, TG7-15, TG7-95) superior cervical ganglion of the sympathetic trunk, via external carotid n. distributes along external carotid artery brs. vascular smooth muscle, arrector pili muscles, sweat glands of face & upper neck postganglionic sympathetic nerve fibers use arteries as roadways to enter the head and neck (Latin, plexus = a braid)
carotid plexus, internal (N130, TG7-15, TG7-95) superior cervical ganglion of sympathetic trunk, via internal carotid n. most distribute along the internal carotid artery brs., although deep petrosal n. is an exception vascular smooth muscle of brain, orbit, forehead, upper nasal cavity; arrector pili muscles of forehead & ant. scalp; sweat glands of forehead; dilator pupillae postganglionic sympathetic nerve fibers use arteries as roadways to enter the head and neck (Latin, plexus = a braid)
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.
brachial plexus (N30, N430, TG7-14, TG2-14)ventral primary rami of C5-8 & T1dorsal scapular, long thoracic, n. to subclavius, suprascapular, lateral & medial pectoral, medial brachial & antebrachial cutaneous, upper, middle & lower subscapular, musculocutaneous, ulnar, median, axillary, radialmuscles of upper limb, excluding trapeziusskin of upper limbplexus is a latin word meaning "braid"; axons from spinal cord levels C5-T1 are mixed (braided) in the brachial plexus and repackaged into terminal branches so that each branch contains axons from several spinal cord levels (Latin, plexus = a braid)
dorsal scapular (N430, N477, TG2-14, TG2-13)brachial plexus (C5)rhomboid major & minor; levator scapulaeno cutaneous branchespasses through scalenus medius
long thoracic (N429, N430, TG2-14, TG2-13) brachial plexus (C5-C7)serratus anteriorno cutaneous brancheslocated on superficial surface of serratus anterior; lesion causes scapular winging, hence the saying "C5, 6, & 7 keep the wings from heaven"
suprascapular (N424,N430, N477, TG2-14, TG2-13)superior trunk of brachial plexus (C5-C6)supraspinatus, infraspinatusno cutaneous branchespasses through scapular notch inferior to the superior transverse scapular ligament

Arteries

ArterySourceBranchesSupplyNotes
subclavian (N33, N136, TG7-15A, TG7-15B) brachiocephalic (right), aortic arch (left)1st part: vertebral, thyrocervical trunk, internal thoracic; 2nd part: costocervical trunk; 3rd part: dorsal scapular (70%); axillary a. is the continuation at lat. border of rib 1neck, spinal cord, thyroid gland & larynx, shoulder, chest muscles, upper limbant. scalene muscle passes anterior to subclavian, dividing it into 3 parts
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
ascending pharyngeal external carotid pharyngeal brs., inf. tympanic, post. meningeal pharynx arises from the medial side of the external carotid a. close to the birfurcation
vertebral (N33, N136, TG7-15, TG7-72)subclavian (1st part)spinal brs., muscular brs., ant. spinal, post. inf. cerebellar, medullary brs., meningeal brs., basilar (fusion of paired vertebrals)deep neck, cervical spinal cord, hindbrainanastomoses with internal carotid in cerebral arterial circle (of Willis); courses through transverse foramina of vertebrae C1-C6
thyrocervical trunk (N33, N136, TG7-15A, TG7-15B) subclavian, 1st partinferior thyroid, transverse cervical, suprascapularlower neck, posterior shoulder, thyroid glanda short thick trunk
cervical, transverse (N33, N184, TG1-13, TG7-14, TG7-15A, TG7-15B)thyrocervical trunkmusculartrapezius muscle & surrounding musclesmay give off the dorsal scapular a. (30%)
suprascapular (N33, N427, TG2-15, TG7-14, TG7-15A, TG7-15B) thyrocervical trunkmuscularsupraspinatus & infraspinatus, shoulder jointanastomoses with circumflex scapular, dorsal scapular & deep br. of transverse cervical
thyroid, inferior (N33, N136, TG7-14, TG7-15A,TG7-15B)thyrocervical trunkascending cervical, inferior laryngeal, esophageal brs., tracheal brs., glandular brs.thyroid gland, lower larynx, upper trachea & esophagus, neck muscles
thoracic, internal (N33, N136, TG7-15A, TG7-15B, TG4-09)subclavian, 1st partanterior intercostal aa., musculophrenic, superior epigastricanterior chest wall, anterior portion of intercostal spacescommonly called "internal mammary" in clinical settings
costocervical trunk (N33, N130, TG7-14, TG7-15A, TG7-15B) subclavian, 2nd partdeep cervical & supreme intercostalmuscles of neck posteriorly; first 2 posterior intercostal spaceslocated between anterior & middle scalene muscles
scapular, dorsal (N33, N410, TG2-09, TG7-14, TG7-15A, TG7-15B)subclavian, end of 3rd partmuscularlevator scapulae, rhomboideus major & minor mm.anasotmoses with suprascapular & subscapular aa.; a branch of the transverse cervical a. in 30% of cases

Veins

VeinTributariesDrains IntoRegion Drained Notes
brachiocephalic (N70,N74, TG4-19)union of subclavian & internal jugular; vertebral, thymic, inferior thyroid, internal thoracic, 1st post. intercostal, left superior intercostal (to left brachiocephalic)left & right brachiocephalic vv. unite to form superior vena cavahead, neck, upper limb, anterior chest wall at its origin, left brachiocephalic receives thoracic duct, right receives right lymphatic duct
external jugular (TG4-02)formed by the union of the retromandibular & posterior auricular vv.; tributaries: posterior external jugular, transverse cervical, suprascapular, anterior jugularsubclavian v. head & neck, shoulder
internal jugular (TG4-19) 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 nead and neck
pharyngeal plexus internal jugular pharynx connects with pterygoid plexus (Latin, plexus = a braid)

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.
thoracic duct (N238, N239, N264, TG4-44, TG5-37) between esophagus & thoracic vertebral bodiesunion of lumbar lymph trunks, sometimes dilated to form cisterna chylijunction of the left subclavian and left internal jugular vv.all of the body and limbs below the diaphragm; the left side of the body, limbs, head and neck above the diaphragmthe largest lymph vessel; passes up through aortic hiatus on right side of aorta, swings to left side of esophagus at T4-T5 intervertebral disc (at the level of the sternal angle)

Topographic Anatomy

Structure/Space Boundaries/Description Significance
carotid bifurcation (N69, N136, TG7-19, TG7-71) point at which the carotid artery splits into external and internal carotids location of carotid body

Viscera/Fascia

Organ Location/Description Notes
carotid body small reddish-brown ovoid mass that lies on the medial side of the carotid bifurcation serves as a chemoreceptor that monitors the amount of oxygen in the blood
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
carotid sinus a slight dilation of the internal carotid artery serves as a baroreceptor that reacts to changes in arterial pressure
pharyngobasilar fascia blends with the periosteum of the base of the skull and defines the limits of the pharyngeal wall in its superior part
fascia, prevertebral deep fascia surrounding vertebral column and associated muscles, including scalene ms. (scalene fascia)
fascia, scalenepart of prevertebral fascia covering scalene mm. reinforces cervical pleura (known there as Sibson's fascia)

Clinical Terms

Term Definition
subclavian "stick"/central venous line catheterization the right subclavian vein is often the point of entry to the venous system for central line placement to administer parenteral (nutritional) fluids and medications and to measure central venous pressure. When using the infraclavicular approach, the physician inserts the needle along the inferior surface of the middle part of the clavicle and moves it medially toward the jugular notch in the manubrium and along the posterior surface of the clavicle where the subclavian vein ascends. If the needle is not inserted carefully, it may tear the subclavian vein and parietal pleura, resulting in hemothorax (bleeding into the pleural cavity). Furthermore, if the needle goes too far posteriorly, it may enter the subclavian artery. Once the needle is inserted, a soft, flexible catheter is inserted into the subclavian vein to be used as a guide.
thoracic outlet syndrome condition due to compromise of blood vessels or nerve fibers between the armpit (axilla) and base of the neck.
cervical rib a rib which arises from the seventh cervical vertebrae (above the normal first rib). Occurs in only about 0.5% of people. May cause nerve and artery problems
scalenus anticus syndrome a syndrome in which the nerves and vessels (lower brachial plexus and subclavian artery) passing between the anterior scalene muscle and a cervical rib are compressed causing pain over the shoulder and radiating down the arm or over the back of the neck.
subclavian steal syndrome aortic arch syndrome, also referred to by many as vertebral-basilar artery disease, carotid artery occlusive syndrome and subclavian steal syndrome is characterized by a constellation of signs and symptoms which occur secondary to abnormalities in the major arteries which extend off of the aortic arch. These abnormalities are structural and most often secondary to the effects of atherosclerosis, blood clots, trauma or a congenital abnormality. Symptoms of this condition include various neurologic symptoms, reduction in pulse and changes in blood pressure.
Virchow's node also called a signal node. An enlarged supraclavicular lymph node, usually on the left side, which is often the first sign of an abdominal tumor (such as stomach cancer).
carotid stenosis & endarterectomy carotid stenosis is a result of atherosclerotic thickening of the intima of the carotid artery. Partial occlusion of this artery may cause transient ischemic attack - a sudden focal loss of neurological function (e.g., dizziness and disorientation) that disappears within 24 hours. Arterial occlusion can also lead to a minor stroke - loss of neurological function such as weakness or sensory loss on one side of the body that exceeds 24 hours but disappears within 3 weeks. The symptoms resulting from carotid stenosis depend on the degree of bloodflow obstruction. To help the situation endarterectomies are performed in which part of the athersclerotic plaque on the intima is stripped off. The common site for this procedure is the internal carotid artery just superior to its origin. Drugs are administered after the procedure to inhibit clot formation. Cranial nerve injury can occur during this procedure to the following nerves: glossopharyngeal, vagus, accessory, hypoglossal, and superior laryngeal nerves. (Greek, stenosis = a narrowing)
radical neck dissection the most commonly performed major operation for head and neck malignancies, most of which are squamous cell carcinomas. The neck is opened laterally, the majority of the sternocleidomastoid muscle is removed, as are the regional cervical lymph nodes, the jugular vein, the spinal accessory nerve, the submaxillary gland and most of the parotid gland. There are several modifications.
Horner's syndrome nerve condition which involves a drooping eyelid (ptosis), constricted pupil (miosis), enophthalmos and lack of sweating on one side of the face. Often seen in association with injury (for example neck fracture, penetrating injury) to the cervical sympathetic nerve trunk in the neck or a Pancoast tumor (tumor of the cupula region) involving both the upper and lower brachial plexus.

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.