Anterior Triangle of the Neck


         Moore's Clinically Oriented Anatomy: 1012-1025

         Grant's Di...

           o     Superior - Inferior border of the mandible
           o  ...
    Hypoglossal n. (XII)
                          Vagus n. (X)
                                Superior laryngeal n.
      Superficial part of the submandibular gland
                                  Facial a. & v.
thyroid                           the large anterior cartilage     connected above to the hyoid bone via the thyrohyoid
mandibular                              both muscles
thyrohyoid           oblique line   lower border elevates the larynx;       ansa cervicalis superior thyroid a.     thyroh...
carotid         superior cervical     most distribute      vascular smooth            none            postganglionic
lower pharynx, larynx                      the inferior laryngeal br.

   Artery          Source                   Branches                      Supply to                         Note...
structures posterior to      distribution
                                                                   the ear

thyroid gland                                             the thyroid        superficial to the common
nodes             carotid sheath     vessels and                                                   subdivisions of deep
Organ             Location/Description                                             Notes

esophagus      the portion of th...
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  1. 1. Anterior Triangle of the Neck ASSIGNMENTS Moore's Clinically Oriented Anatomy: 1012-1025 Grant's Dissector: 256-262; Start at "Anterior Triangle of Neck", Stop at "Cervical Viscera" HELPFUL HINTS 1. Finding the accessory nerve - You have already dissected this structure in the back and followed it through the posterior cervical triangle. As you trace it proximally into the sternocleidomastoid muscle notice that it runs superiorly within the muscle to the insertion end. You can see it there on the deep surface of the muscle (close to the mastoid process) only if you transect the sternocleidomastoid and reflect the superior half in a superior direction to expose the deep surface of the muscle. The nerve should be seen on the deep surface of the muscle within an inch of the insertion. 2. Hypoglossal nerve and ansa cervicalis - The approach described in Grant's Dissector (pg. 257) to find the superior ramus of the ansa cervicalis has met with limited success in the past. Try this: Pick up the superior belly of the omohyoid muscle and look for its motor nerve (Netter plate 26). This nerve comes to omohyoid from its lateral edge. The nerve to omohyoid is often clearly seen in the cervical fascia, which is translucent. Follow this nerve using blunt dissection and it will lead you to the ansa cervicalis. No omohyoid nerve? Try the nerve to sternohyoid or sternothyroid 3. Lingual and facial arteries - It is very tempting to count the branches coming off of the anterior surface of the external carotid artery and assign names based on relative position of branching. If you don't have enough branches, dissect the facial artery for a short distance and see if the lingual artery comes off as a branch of it (~20%). Always confirm your identification of vessels by visualizing the field of distribution of each branch. WHEN YOU FINISH THIS SECTION, YOU SHOULD BE ABLE TO PERFORM THE FOLLOWING TASKS AND ANSWER THESE QUESTIONS 1. What vascular structures are found in the carotid triangle? 2. What is the spinal cord level of origin of the ansa cervicalis? What does it innervate? 3. Describe the relationship of the vagus n., the common carotid a. and internal jugular v. in the carotid sheath. 4. What is the relationship of the sympathetic trunk to the carotid sheath at the C4 vertebral level? 5. Where is a good location to palpate the carotid pulse? 6. What would be teh function of the carotid body at high elevation (reduced oxygen)? What effect would theis have on heart rate? 7. List the muscles of the muscular triangle. What is the source of their innervation? 8. If you were performing surgery in the muscular triangle, what vascular structures would you be likely to encounter?
  2. 2. ANTERIOR TRIANGLE OF THE NECK Boundaries o Superior - Inferior border of the mandible o Lateral - Anterior border of the sternocleidomastoid m. o Medial - Midline of the neck Subdivisions o Muscular triangle o Carotid triangle o Submandibular triangle o Submental triangle MUSCULAR TRIANGLE Boundaries o Superior - Body of the hyoid bone o Medial - Midline of the neck o Inferolateral - Anterior border of the sternocleidomastoid m. o Superolateral - Superior belly of the omohyoid m. Contents o Muscles  Sternohyoid  Sternothyroid  Thyrohyoid o Nerves  Ansa cervicalis o Viscera  Thyroid gland  Lobes (2)  Isthmus  Parathyroid glands  Larynx (To be studied in detail at a later date) CAROTID TRIANGLE Boundaries o Anterior - Superior belly of the omohyoid m. o Posterior - Anteror border of the sternocleidomastoid m. o Superior - Posterior belly of the digastric m. Contents of the carotid triangle o Carotid sheath and its contents o Nerves
  3. 3.  Hypoglossal n. (XII)  Vagus n. (X)  Superior laryngeal n.  Internal br.  External br.  Cardiac brs.  Ansa cervicalis  Superior root  Inferior root  Branches to infrahyoid mm. o Vessels  Arteries  Internal carotid a.(no branches in the neck)  External carotid a.  Superior thyroid a.  Ascending pharyngeal a.  Lingual a.  Occipital a.  Facial a.  Carotid sinus  Carotid body  Veins accompany the arteries listed above. Some have the same names as the arteries and some (internal and external jugular vv.) do not. CERVICAL PORTION OF THE SYMPATHETIC TRUNK Superior cervical ganglion o Internal carotid n. o External carotid n. Middle cervical ganglion Cervicothoracic (stellate) ganglion SUBMANDIBULAR REGION Boundaries of the submandibular triangle o Superior - Base of the mandible o Anterior - Anterior belly of the digastric m. o Posterior - Posterior belly of the digastric m. Contents of the submandibular triangle o Superficial structures (those lying superficial to the plane of the mylohyoid m.)  Platysma  Submental a. & v.  Nerves  Cervical brs. of the facial n.  N. to mylohyoid
  4. 4.  Superficial part of the submandibular gland  Facial a. & v.  Muscles  Anterior belly of the digastric m.  Stylohyoid m.  Mylohyoid m. o Deep structures of the submandibular region (those lying deep to the plane of the mylohyoid m.) will be dissected with the floor of the mouth. SUBMENTAL TRIANGLE Boundaries o Medial - Midline of the neck o Lateral - Anterior belly of the digastric m. o Inferior - Body of the hyoid bone Contents o Mylohyoid muscle (deep) o Submental a. and v. ANATOMY TABLES FOR TODAY'S TOPIC Osteology Bone/Cartilage Structure Description Notes cricoid cartilage the inferior & posterior connected: above to the thyroid cartilage via the inferior cartilage of the larynx; it horn of the thyroid cartilage, to the conus elasticus, to forms a complete the arytenoid cartilages which sit atop the lamina; cartilaginous ring; its arch connected below to the first tracheal ring via the projects anteriorly and its cricotracheal ligament lamina is broad and flat posteriorly hyoid a "U"-shaped bone the hyoid bone ossifies completely in middle life; the consisting of several parts: body articulates with the greater horns via cartilage and body, 2 greater horns, 2 with the lesser horns via fibrous joints prior to lesser horns ossification; an important site for muscle attachments (suprahyoid and infrahyoid muscle groups) body the middle portion of the the body of the hyoid bone articulates with the greater "U"-shaped bone horns posteriorly greater horn posteriorly directed limbs of each greater horn articulates with the body and lesser (cornu) the "U"-shaped bone horns anteriorly; origin of middle pharyngeal constrictor m. and hyoglossus m. lesser horn articulates with the greater the inferior end of the stylohyoid ligament attaches to (cornu) horn at its junction with the the lesser horn body
  5. 5. thyroid the large anterior cartilage connected above to the hyoid bone via the thyrohyoid cartilage of the larynx; it has several membrane; connected below to the cricoid cartilage via parts: laminae (2), superior the inferior horn of the thyroid cartilage; connected horns (2), inferior horns (2), posteriorly: to the arytenoid cartilage via the vocal oblique line, superior ligament and thyroarytenoid m., to the epiglottic thyroid notch, 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 the laryngeal prominence is the line of fusion of the two forming one side of the laminae; each lamina is connected superiorly to the thyroid cartilage; two hyoid bone by the thyrohyoid membrane laminae fuse anteriorly in the midline to form the thyroid cartilage superior horn the rounded, superior it is connected superiorly to the greater horn of the hyoid projection of the posterior bone by the lateral thyrohyoid ligament border of the thyroid lamina inferior horn the rounded, inferior it is connected inferiorly to the cricoid cartilage by the projection of the posterior cricothyroid articulation (a synovial joint) border of the thyroid lamina oblique line ridge which descends a line of muscle attachment diagonally from superior to inferior on the lateral surface of the thyroid lamina laryngeal the line of fusion of the known to the lay person as the "Adam's apple"; the prominence thyroid laminae 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 the notch at the superior end it is connected to the hyoid bone by the median thyroid notch of the laryngeal prominence thyrohyoid ligament Muscles Muscle Origin Insertion Action Innervation Artery Notes digastric anterior body of the elevates the hyoid anterior belly: anterior belly: the digastric m. belly: hyoid via a bone; depresses the mylohyoid submental a.; forms two sides digastric fibrous loop mandible nerve, from the posterior belly: of the fossa of the over an mandibular occipital a. submandibular mandible; intermediate division of the triangle; it is posterior tendon trigeminal formed from belly: nerve (V); mesenchyme mastoid posterior belly: derived from the notch of the facial nerve first two temporal (VII) pharyngeal bone arches, hence its dual innervation mylohyoid mylohyoid midline elevates the hyoid mylohyoid mylohyoid branch of the nerve to line of raphe and bone and the nerve from the the inferior alveolar mylohyoid also mandible body of the tongue; depresses inferior alveolar a. innervates the hyoid bone the mandible nerve, a branch anterior belly of of the digastric m.;
  6. 6. mandibular both muscles division of the are derivatives trigeminal of the second nerve (V) pharygneal arch omohyoid inferior inferior depresses/stabilizes ansa cervicalis transverse cervical the intermediate belly: upper belly: the hyoid bone a. tendon of border of the intermediate omohyoid is scapula tendon; tethered to the medial to the superior clavicle by a scapular belly: lower fascial sling notch; border of the superior hyoid bone belly: lateral to the intermediate sternohyoid tendon insertion platysma fascia inferior draws the corners of cervical branch facial a. platysma is overlying the border of the the mouth down; it of the facial derived from the pectoralis mandible aids in depression nerve (VII) mesenchyme of major and and skin of of the mandible the second deltoid lower face pharyngeal arch muscles sternocleidomastoid sternal head: mastoid draws the mastoid spinal accessory sternocleidomastoid carotid sheath anterior process and process down nerve (XI), with branch of the structures lie surface of lateral 1/2 of toward the same sensory supply occipital a. deep to it the the superior side which causes from C2 & C3 manubrium; nuchal line the chin to turn up (for clavicular toward the opposite proprioception) head: medial side; acting 1/3rd of the together, the clavicle muscles of the two sides flex the neck sternohyoid posterior lower border depresses/stabilizes ansa cervicalis superior thyroid a. sternohyoid surfaces of of the hyoid the hyoid bone overlies the both the bone, medial sternothyroid manubrium to the and thyrohyoid and sternal omohyoid mm. end of the m. insertion clavicle sternothyroid posterior oblique line depresses/stabilizes ansa cervicalis superior thyroid a. sternothyroid surface of of the the hyoid bone lies deep to the the thyroid sternohyoid m. manubrium cartilage below the origin of the sternohyoid m. stylohyoid posterior splits around elevates and retracts facial nerve ascending facial nerve side of the the the hyoid bone (VII) pharyngeal a. innervates both styloid intermediate the stylohyoid process tendon of the m. and the digastric m. posterior belly to insert on of the digastric the body of m. shortly after the hyoid exiting from the bone stylomastoid foramen
  7. 7. thyrohyoid oblique line lower border elevates the larynx; ansa cervicalis superior thyroid a. thyrohyoid lies of the of the hyoid depresses/stabilizes (via fibers deep to the thyroid bone the hyoid bone running with sternohyoid cartilage the hypoglossal nerve that leave XII distal to the superior limb of ansa) Nerves Nerve Source Branches Motor Sensory Notes accessory cranial root: no named GSE: none also known as: CN XI, medulla - nucleus branches sternocleidomastoid 11th cranial nerve; spinal ambiguus; spinal and trapezius mm. root enters cranial cavity root: spinal nucleus by passing through the of the upper foramen magnum; exits cervical spinal cord 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 superior root (C1 to infrahyoid omohyoid m., none superior and inferior cervicalis and C2) and muscles sternohyoid m., roots of the ansa inferior root (C2 sternothyroid m., cervicalis are also known and C3) of the ansa thyrohyoid m., as the anterior and cervicalis geniohyoid m. posterior roots cardiac, cervical no named heart (sympathetic: heart, cervical sympathetic sympathetic sympathetic trunk branches increases rate and force bronchial trunk usually gives 3 of contraction, tree and cervical cardiac brs. l parasympathetic: lungs (superior, middle and decreases rate and inferior) to the cardiac force of contraction); plexus bronchial tree & lungs via pulmonary plexus cardiac, vagal vagus n. (X) no named heart (parasympathetic: heart, vagus n. has 2 cervical branches decreases rate and bronchial cardiac brs. (superior force of contraction; tree and and inferior) and 1 or sympathetic: increases lungs more thoracic cardiac rate and force of brs. contraction); bronchial tree and lungs via pulmonary plexus carotid superior cervical distributes along vascular smooth none postganglionic plexus, ganglion of the the brs. of the muscle, arrector pili sympathetic nerve fibers external sympathetic trunk, external carotid muscles, sweat glands use arteries as roadways via the external artery of face & upper neck to enter the head and carotid n. neck
  8. 8. carotid superior cervical most distribute vascular smooth none postganglionic plexus, ganglion of the along the brs. of muscle of the brain, sympathetic nerve fibers internal sympathetic trunk, the internal orbit, forehead, upper use arteries as roadways via the internal carotid artery, nasal cavity; arrector to enter the head and carotid n. although the pili muscles of neck deep petrosal n. forehead and anterior is an exception scalp; sweat glands of because it runs a the forehead; dilator short course pupillae m. independent of an artery cervicofacial facial (VII) buccal br., muscles of facial none cervicofacial division division marginal expression of the lower usually forms a loop by mandibular br., part of the face; communication with the cervical br. platysma m. temporofacial division of the facial n. hypoglossal medulla: no named intrinsic and extrinsic none also known as: CN XII, n. hypoglossal branches; muscles of the tongue 12th cranial nerve; the nucleus branches of the (except the hypoglossal n. exits the ventral primary palatoglossus m.) posterior cranial fossa by ramus of spinal passing through the nerve C1 are hypoglossal canal; the carried by this superior root of the ansa nerve and are not cervicalis travels with considered to be the hypoglossal n. for a branches of the short distance hypoglossal nerve inferior recurrent laryngeal no named all intrinsic muscles of mucous inferior laryngeal n. is laryngeal n. br. of the vagus n. branches the larynx except the membrane the continuation of the (X) cricothyroid; those of the larynx recurrent laryngeal n., muscles are: below the the name change occurs thyroarytenoid, oblique vocal fold at the cricothyroid and transverse articulation arytenoid, posterior and lateral cricoarytenoid, aryepiglottic, thyroepiglottic, vocalis; secretomotor to the mucous membrane of the larynx below the vocal fold mylohyoid, n. inferior alveolar n., no named mylohyoid m., anterior none n. to mylohyoid arises to a branch of the branches belly of the digastric near the lingula of the mandibular division m. mandible; course within of the trigeminal n. the mylohyoid groove of (V3) the mandible recurrent vagus n. (X) esophageal brs., upper esophagus, upper right recurrent laryngeal laryngeal n. tracheal brs., lower pharynx, esophagus, n. loops posteriorly cardiac brs., laryngeal mm. (except lower around the right pharyngeal brs., cricopharyngeus); pharynx, subclavian a.; left inferior laryngeal smooth muscle of the larynx below recurrent laryngeal n. n. trachea; secretomotor the vocal loops posteriorly around to mucosal glands in folds, GVA the aortic arch and the upper esophagus, from heart ligamentum arteriosum;
  9. 9. lower pharynx, larynx the inferior laryngeal br. below the vocal fold, supplies all intrinsic trachea; cardiac muscle muscles of the larynx of the heart (slows EXCEPT the heart rate, decreases cricothyroid m. force of contraction) superior vagus (X) internal & cricothyroid, inferior mucous external br. supplies laryngeal external brs. pharyngeal constrictor, lining of cricothyroid m.; all other secretomotor to larynx above intrinsic muscles of the mucous glands of vocal folds larynx are supplied by larynx above vocal the recurrent laryngeal folds nerve superior vagus n. (X) internal br., cricothyroid m., mucous external br. supplies the laryngeal n. external br. inferior pharyngeal membrane cricothyroid m.; all other constrictor m.; of the larynx intrinsic muscles of the secretomotor to above the larynx are supplied by mucosal glands of the vocal folds the recurrent laryngeal n. larynx above the vocal folds sympathetic preganglionic postganglionic dilator pupillae m.; pain from located parallel to the chain ganglia, sympathetic fibers sympathetic vascular smooth viscera vertebral bodies in the cervical arrive via white depart via gray muscle; arrector pili neck; there are no white rami rami muscles and sweat rami communicantes at communicantes of communicans to glands of head and cervical levels ventral primary cervical spinal neck; heart and lungs rami of spinal nn.; internal and nerves T1-T5 external carotid nn.; cervical cardiac brs. to carotid glossopharyngeal n. no named none sensory chemoreception (blood body (IX) branches receptors in pH) in carotid body; the carotid blood pressure receptors body and in carotid sinus; both carotid sinus located near the bifurcation of the common carotid a.; the vagus n. (X) may share a role in this innervation vagus n. medulla: dorsal auricular br., SVE: intrinsic muscles GSA: skin also known as: CN X, motor nucleus pharyngeal br., of the larynx, pharynx of the 10th cranial nerve; the (GVE superior (except external vagus n. passes through preganglionic laryngeal, stylopharyngeus), and auditory the jugular foramen to parasympathetic); superior and palate (except tensor meatus; exit the posterior cranial inferior ganglion inferior cervical veli palatini); GVE: GVA: fossa; vagus means (GVA); nucleus cardiac brs., smooth muscle of the viscera of "wanderer" in reference ambiguus (SVE); recurrent respiratory tree & gut head, neck, to its extensive superior ganglion laryngeal n., (proximal to the left thorax & distribution to the body (GSA); inferior thoracic cardiac colic flexure), heart; abdomen cavities ganglion(SVA) brs., brs. to the secretomotor: mucous proximal to pulmonary glands of the larynx, the left colic plexus, brs. to respiratory tree, flexure; the esophageal pharynx and gut; SVA: taste plexus, anterior secretomotor to from the and posterior digestive glands epiglottis vagal trunks
  10. 10. Arteries Artery Source Branches Supply to Notes ascending external carotid a. pharyngeal brs., inferior pharynx, meninges ascending pharyngeal a. arises pharyngeal tympanic a., posterior from the medial side of the meningeal a. external carotid a. close to the birfurcation common brachiocephalic external carotid a., internal most of the head and common carotid a. bifurcates carotid trunk (right), carotid a. upper neck at the level of the superior aortic arch (left) 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 common carotid superior thyroid a., upper neck, face and external carotid a. is the carotid ascending pharyngeal a., scalp primary blood supply to the lingual a., facial a., face and superficial head; the occipital a., posterior maxillary a. and superficial auricular a., maxillary a., temporal a. are its terminal superficial temporal a. branches facial external carotid a. ascending palatine a., lower part of the the angular branch of the facial tonsilar br., submental a., palatine tonsil, a. anastomoses with the superior labial a., inferior submandibular gland, ophthalmic a. labial a., lateral nasal a., facial muscles and angular a. fascia inferior inferior thyroid a. no named branches internal part of the inferior laryngeal a. laryngeal inferior larynx accompanies the inferior laryngeal n. inferior thyrocervical ascending cervical a., thyroid gland, lower inferior thyroid a. gives rise to thyroid trunk inferior laryngeal a., larynx, upper trachea, the ascending cervical a. as it esophageal brs., tracheal upper esophagus, deep arches medially brs., glandular brs. neck muscles internal common carotid none in the neck; in the brain; eye and orbit; internal carotid a. is the carotid a. head: ophthalmic a., forehead primary blood supply to the posterior communicating brain; it anastomoses with the a., anterior cerebral a., vertebral aa. and the middle cerebral a. 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 tongue, suprahyoid lingual a. is the 2nd branch off lingual brs., deep lingual a., muscles, palatine tonsil of the anterior side of the sublingual a. external carotid a.; it may arise in common with the facial a. occipital external carotid a. sternocleidomastoid brs., lateral neck, posterior occipital a. anastomoses with auricular br., mastoid br., neck, posterior scalp the deep cervical a.; it courses descending br., occipital with the greater occipital nerve brs. on the posterior surface of the head posterior external carotid a. stylomastoid br., auricular part of the external ear, posterior auricular and greater auricular br., occipital br. scalp and deeper occipital share their region of
  11. 11. structures posterior to distribution the ear submental facial a. no named branches muscles, skin and fascia submental a. supplies the under the chin; submandibular gland and the submandibular gland mylohyoid m. in addition to the skin and superficial fascia superior superior thyroid a. no named branches internal aspect of the superior laryngeal a. penetrates laryngeal superior larynx the thyrohyoid membrane in company with the internal br. of the superior laryngeal n. superior external carotid a. infrahyoid br., thyroid gland, upper superior thyroid a. is usually thyroid sternocleidomastoid br., part of the larynx, the first branch of the external superior laryngeal a., infrahyoid mm., carotid a. cricothyroid br., glandular sternocleidomastoid m. brs. thyroidea brachiocephalic a. no named branches isthmus of the thyroid thyroidea ima a. is present in ima or aortic arch gland, upper trachea 10% of individuals; it is clinically significant because it is a midline artery in the region of tracheostomy; ima means "lowest" Veins Regions Vein Tributaries Drains Into Notes Drained anterior jugular submental v, communicating external jugular v. superficial parts anterior jugular v. is v. v. of the anterior valveless neck common facial v. formed by the union of the internal jugular v. face and common facial v. may anterior division of the anterior scalp receive drainage from the retromandibular v. and the lingual v. facial v. external jugular formed by the joining of the subclavian v. head & neck, external jugular v. contains v. retromandibular and posterior shoulder valves that may not be fully auricular vv.; tributaries: functional posterior external jugular v., transverse cervical v., suprascapular v., anterior jugular v. inferior thyroid numerous tributaries from the left and right inferior part of inferior thyroid vv. descend v. thyroid gland, esophageal v, brachiocephalic vv. the thyroid on the anterior surface of the tracheal v., inferior laryngeal gland trachea v. internal jugular formed at the base of the skull brachiocephalic v. brain, cranial internal jugular is the largest v. where the sigmoid sinus ends; cavity, skull, vein of the nead and neck tributaries: pharyngeal vv.; face, viscera of lingual v., common facial v., the neck sternocleidomastoid v., superior thyroid v, middle thyroid v. middle thyroid v. numerous tributaries from the internal jugular v. lateral aspect of middle thyroid v. crosses
  12. 12. thyroid gland the thyroid superficial to the common gland carotid a. posterior small veins of the it unites with the region behind posterior auricular v. auricular v. subcutaneous tissues behind posterior division of the ear communicates with the the ear, stylomastoid v. the retromandibular occipital v. behind the ear v. to form the external jugular retromandibular formed by the union of the anterior and side of the head retromandibular v. is v. superficial temporal v. and posterior divisions of and scalp; deep contained within the parotid maxillary v. the retromandibular face gland; anterior division unites v. 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 sternocleidomastoid v., internal jugular v. superior portion superior thyroid v. is the only v. superior laryngeal v., of the thyroid thyroid v. to accompany an infrahyoid v., cricothyroid v. gland and artery; it crosses superficial surrounding to the common carotid a. structures thyroidea ima v. formed by a high union of the left brachiocephalic inferior part of an occasional branch; a right and left inferior thyroid vein the thyroid midline structure which is in vv. gland danger during tracheostomy Topographic Anatomy Structure/Space Description/Boundaries Significance anterior cervical boundaries: medial - midline; lateral - anterior border of anterior cervical triangle may be triangle the sternocleidomastoid m.; superior - lower border of the subdivided into the carotid triangle and mandible the muscular triangle carotid triangle boundaries: anterior - superior belly of the omohyoid m.; the carotid artery branches here posterior - sternocleidomastoid m.; superior - posterior belly of the digastric m.; anterior cervical boundaries: medial - midline; lateral - anterior border of anterior cervical triangle may be triangle the sternocleidomastoid m.; superior - lower border of the subdivided into the carotid triangle and mandible the muscular triangle muscular triangle boundaries: medial - midline; superior - body of the muscular triangle contains the strap hyoid bone; superolateral - superior belly of the muscles of the neck; larynx and thyroid omohyoid m.; inferolateral - sternocleidomastoid m. gland lie deep to the strap muscles submandibular boundaries: anterior - anterior belly of the digastric m.; submandibular triangle contains the triangle posterior - posterior belly of the digastric m.; superior - submandibular gland lower border of mandible submental triangle boundaries: lateral - anterior belly of the digastric m.; submental triangle contains the medial - midline; inferior - body of the hyoid bone submental a. and v. Lymphatics Afferents Regions Structure Location Efferents to Notes from drained deep cervical in and around lymphatic jugular trunk head and neck superior and inferior
  13. 13. nodes carotid sheath vessels and subdivisions of deep posterior and numerous cervical nodes are lateral to the node groups delineated by the internal jugular from the head crossing of the omohyoid v. and neck m. jugular lymphatic carotid sheath in deep cervical left: thoracic duct near head & neck jugular trunk carries trunk root of neck nodes its termination; right: most of the lymph from right lymphatic duct or the head and neck junction of right subclavian and right internal jugular vv. jugular nodes, along the lymphatic inferior deep cervical skin and mm. anterior jugular nodes anterior anterior jugular vessels from nodes of the anterior are located between the vein the anterior infrahyoid superficial layer of deep inferior part region of the cervical fascia and the of the neck neck infrahyoid mm. jugular nodes, along the lymphatic superior deep cervical inferior part of there are one or two external external jugular vessels from nodes the ear and the nodes in this group v. the side of the parotid region head jugulodigastric anterolateral to superior deep inferior deep cervical oral cavity, a member of the superior node internal jugular cervical nodes nodes tongue, deep cervical node v. where it is palatine tonsil group; important node to crossed by palpate during physical posterior belly exam of the digastric juguloomohyoid lateral to internal superior deep inferior deep cervical submental an important node to node jugular v. where cervical nodes nodes region and tip examine in cases of oral it is crossed by of tongue; head cancer caused by use of superior belly of & neck above tobacco products omohyoid this level juxtavisceral adjacent to the cervical superior deep cervical esophagus, four groups of nodes cervical viscera viscera nodes, inferior deep larynx, trachea juxtavisceral nodes are cervical nodes and thyroid recognized: infrahyoid, gland prelaryngeal, pretracheal and paratracheal submental nodes under the lymphatic submandibular nodes, tip of the submental nodes are mandible on the vessels from juguloomohyoid node tongue, lower important nodes to mylohyoid m. the lower face lip, floor of the examine in cases of oral and chin mouth, chin, cancer caused by the use gums and of tobacco products lower incisor teeth superficial in superficial lymphatic varies by group; head & neck several groups are cervical nodes fascia and along vessels from ultimate destination is designated by location: superficial superficial the jugular trunk occipital, retroauricular, vessels of the structures in anterior auricular, head & neck head & neck superficial parotid, facial, submental, submandibular, external jugular, anterior jugular Viscera of the Neck
  14. 14. Organ Location/Description Notes esophagus the portion of the gastrointestinal connects: superiorly with laryngopharynx at lower border of cricoid tract between the pharynx and the cartilage; inferiorly it passes through diaphragm at the T10 vertebral stomach 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 composed of: thyroid, cricoid, epiglottic, arytenoid, cuneiform & laryngopharynx at level of C4-6 corniculate cartilages; contains the vocal ligaments; controls the vertebrae airway parathyroid four small endocrine glands two pair of glands that develop from the 3rd and 4th pharyngeal glands located on the posterior surface of pouches; they produce parathormone which is important in regulating the lateral lobes of the thyroid serum calcium levels gland pharynx the space posterior to the nasal divided into 3 parts: nasopharynx, oropharynx and laryngopharynx; cavity, oral cavity and larynx the airway and the pathway of ingested foods and liquids cross at this location thyroid gland a large endocrine bland that lies thyroid gland consists of two lateral lobes joined across the midline anterolateral to the lower part of by the isthmus; it may have a pyramidal lobe extending superiorly the larynx and upper trachea 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 constricted midline connection thyroid isthmus lies anterior to tracheal rings 2-4 isthmus between the lateral lobes of the thyroid gland trachea main airway that lies anterior to trachea extends from vertebral level C6 to the level of the T4/5 the esophagus intervertebral disc; superiorly it is connected to the cricoid cartilage via the cricotracheal ligament; it bifurcates into two primary bronchi