Gross Anatomy

Superficial Neck; Posterior Triangle of the Neck; Muscular Triangle of the Neck


Anatomy Tables for Today's Topic


Bones and Cartilages
Muscles
Nerves
Arteries
Veins
Topographic Anatomy
Lymphatics
Fascia
Viscera

Bones and Cartilages

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)
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
mandible the U-shaped bone forming the lower jaw contains the inferior teeth; formed from the mesenchyme of the 1st pharyngeal arch, and its muscles are innervated by the nerve of the 1st arch (mandibular division of cranial nerve V)
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
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¡

Muscles

Muscle Origin Insertion Action Innervation Artery Notes
levator scapulae transverse processes of C1-4 vertebrae medial border of the scapula from the superior angle to the spine elevates scapula dorsal scapular nerve (C5); the upper part of the muscle receives branches of C3 & C4 spinal nerves dorsal scapular a. named for its action
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
scalene, anterior anterior tubercles of the transverse processes of vertebrae C3-C6 scalene tubercle of the first rib elevates the first rib; flexes and laterally bends the neck brachial plexus, C5-C7 ascending cervical a., a branch of the thyrocervical trunk a muscle of inspiration; an important landmark of the neck; it is located between the subclavian vein and the subclavian artery; the roots of the brachial plexus pass posterior to it; the phrenic nerve crosses its anterior surface
scalene, middle posterior tubercles of the transverse processes of vertebrae C2-C7 upper surface of the first rib behind the subclavian artery elevates the first rib; flexes and laterally bends the neck brachial plexus, C3-C8 ascending cervical a. a muscle of respiration (inspiratory); also called scalenus medius; penetrated by the dorsal scapular n. and long thoracic n.
scalene, posterior posterior tubercles of the transverse processes of vertebrae C5-C7 lateral surface of the second rib elevates the second rib; flexes and laterally bends the neck brachial plexus, C7-C8 ascending cervical a. a muscle of respiration (inspiratory); it is the longest of the scalene muscles
splenius ligamentum nuchae and spines C7-T6 capitis: mastoid process & superior nuchal line laterally; cervicis: posterior tubercles of C1-3 extends and laterally bends neck and head; rotates head to same side dorsal primary rami of spinal nerves C2-6 supplied segmentally by: deep cervical a., posterior intercostal aa. splenius means bandage; it gets its name from its broad, flat shape
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
sternohyoid posterior surfaces of both the manubrium and sternal end of the clavicle lower border of the hyoid bone, medial to the omohyoid m. insertion depresses/stabilizes the hyoid bone ansa cervicalis superior thyroid a. sternohyoid overlies the sternothyroid and thyrohyoid mm.
sternothyroid posterior surface of the manubrium below the origin of the sternohyoid m. oblique line of the thyroid cartilage depresses/stabilizes the thyroid cartilage ansa cervicalis superior thyroid a. sternothyroid lies deep to the sternohyoid m.
thyrohyoid oblique line of the thyroid cartilage lower border of the hyoid bone elevates the larynx; depresses/stabilizes the hyoid bone ansa cervicalis (via fibers running with the hypoglossal nerve that leave XII distal to the superior limb of ansa) superior thyroid a. thyrohyoid lies deep to the sternohyoid

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
brachial plexus ventral primary rami of C5-8 and T1 dorsal scapular, long thoracic, n. to subclavius, suprascapular, lateral and medial pectoral, medial brachial and antebrachial cutaneous, upper, middle and lower subscapular, musculocutaneous, ulnar, median, axillary, radial muscles of the upper limb, excluding trapezius skin of the upper limb plexus 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 segmental levels
cervical plexus ventral primary rami of spinal nerves C1-C4 brs. to: longus colli & capitis, sternocleidomastoid m., trapezius m., levator scapulae m., scalenus medius m., rectus capitis anterior and lateralis mm.; superior & inferior root of the ansa cervicalis, n. to the thyrohyoid m., n. to the geniohyoid m., lesser occipital n., great auricular n., transverse cervical n., supraclavicular nn. (medial, intermediate and lateral), contributions to the phrenic n. from C3 and C4 longus colli & capitis mm., rectus capitis anterior & lateralis mm., infrahyoid mm., thyrohyoid m., geniohyoid m., respiratory diaphragm skin of the anterolateral neck; skin of the ear and skin behind the ear close association of the supraclavicular nn. to the phrenic n. results in pain from the respiratory diaphragm referred to the shoulder
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.
great auricular n. cervical plexus (contributions from the ventral primary rami of spinal nerves C2&C3) mastoid n., auricular n. none skin of the ear and skin below the ear the great auricular n. crosses the superficial surface of the sternocleidomastoid m.
lesser occipital n. ventral primary ramus of spinal nerve C2 no named branches none skin behind the ear lesser occipital n. arises from the cervical plexus
supraclavicular, intermediate cervical plexus (C3&C4) no named branches none skin of the root of the neck and upper chest, near the mid-clavicle pain from respiratory diaphragm is referred to the shoulder
supraclavicular, lateral cervical plexus (C3&C4) no named branches none skin of the root of the neck and upper shoulder pain from respiratory diaphragm is referred to the shoulder
supraclavicular, medial cervical plexus (C3&C4) no named branches none skin of the root of the neck and upper chest, anteriorly pain from respiratory diaphragm is referred to the shoulder
transverse cervical n. cervical plexus (C2 and C3) no named branches none skin of the anterior surface of the neck transverse cervical n. penetrates the platysma m. but does not innervate it

Arteries

Artery Source Branches Supply to Notes
subclavian brachiocephalic a. (right), aortic arch (left) 1st part: vertebral a., thyrocervical trunk, internal thoracic a.; 2nd part: costocervical trunk; 3rd part: dorsal scapular a. (70%) neck, brain, spinal cord, thyroid gland, larynx, shoulder, chest muscles, upper limb subclavian a. is continuous with the axillary a., the name change occurs at the lateral border of the first rib; anterior scalene muscle passes anterior to the subclavian a., dividing it into 3 parts

Veins

Vein Tributaries Drains Into Regions Drained Notes
jugular, anterior submental v, communicating v. external jugular v. superficial parts of the anterior neck anterior jugular v. is valveless
jugular, external 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

Topographic Anatomy

Structure/Space Description/Boundaries Significance
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
cervical triangle, anterior 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
cervical triangle, posterior boundaries: anterior - sternocleidomastoid m.; posterior - trapezius m.; inferior - middle 1/3 of the clavicle posterior cervical triangle may be subdivided by the inferior belly of the omohyoid m. to form an omoclavicular triangle; the external jugular vein crosses the posterior cervical 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
omoclavicular triangle boundaries: superior - inferior belly of the omohyoid m.; anterior - sternocleidomastoid m.; inferior - middle 1/3 of the clavicle the external jugular vein courses deeply through the omoclavicular triangle
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.
deep cervical nodes, inferior around the internal jugular v., inferior to the crossing of the omohyoid m. superior deep cervical nodes; numerous node groups of the neck jugular trunk head and neck inferior deep cervical nodes are in direct continuity with the superior deep cervical chain of nodes
deep cervical nodes, superior around the internal jugular v., superior to the crossing of the omohyoid m. numerous node groups of the head and upper neck, including retropharyngeal nodes and deep parotid nodes inferior deep cervical nodes head and the superior part of the neck the superior deep cervical node group has many large nodes; the jugulodigastric and juguloomohyoid nodes are members of this group

Fasciae of the Neck

Structure Location/Description Notes
fascia, alar anterior lamina of the prevertebral fascia, attaching anteriorly to visceral fascia behind esophagus in the superior thorax alar fascia separates the retropharyngeal space above from the posterior mediastinum below
fascia, buccopharyngeal posterior part of the visceral fascia of the neck buccopharyngeal fascia lies behind the pharynx and esophagus
fascia, infrahyoid deep fascia covering the infrahyoid muscles infrahyoid fascia is composed of two layers: a superficial layer associated with the sternohyoid and omohyoid mm. and a deep layer associated with the sterhothyroid and thyrohoid mm.
fascia, pharyngobasilar submucosa of the pharynx pharyngobasilar fascia is attached to the base of skull and is best seen above the superior edge of the superior pharyngeal constrictor m.
fascia, pretracheal anterior part of the visceral fascia of the neck pretracheal fascia covers the larynx,/trachea and thyroid gland
fascia, prevertebral deep fascia surrounding vertebral column and associated muscles prevertebral fascia covers the scalene mm. where it is called scalene fascia
fascia, scalene part of the prevertebral fascia covering the scalene mm. reinforces the cervical pleura (known there as Sibson's fascia) and extends out onto the ventral primary rami of spinal nn. C5-T1 as the axillary fascia
fascia, superficial layer of deep cervical deep fascia investing all of the deep neck structures superficial layer of deep cervical fascia extends between the trapezius m. and sternocleidomastoid m.. in the posterior cervical triangle and between the paired sternocleidomastoid mm. in the anterior cervical triangle
fascia, visceral deep fascia enclosing the visceral structures of the neck (thyroid gland, larynx, trachea, esophagus) the anterior part is also known as pretracheal fascia; the posterior part also known as buccopharyngeal fascia

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

Other Tables of Interest:

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Tables Organized by System Tables Organized by Region


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 2007, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences.

Unauthorized use is prohibited.