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Anatomy - Triangles of Neck

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					                                                     Anterior Triangle of Neck



                      Osteology
           Bone            Structure                Description
mandible            mental protuberance      forms bone of chin
                                             anteriorly
hyoid               body                     articulates 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                            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)
                                      Anterior Triangle of Neck
occipital                     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
            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                      the bone forming the
                              lateral side of the skull,
                              temporal refers the
                              passage of time, which
                              is marked by the
                              appearance of gray hair
                              on the side 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)
                                                   Anterior Triangle of Neck



thyroid cartilage                          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. & thyroartenoid
                                           m., posteriorly to
                                           epiglottic cart. via
                                           thyroepiglottic lig.; tilts
                                           forward to increase
                                           tension on vocal lig. &
                                           increase pitch of voice

                    lamina                 two 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 line           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


                                                               Muscles
         Muscle              Origin                Insertion             Action   Innervation   Notes
                                                    Anterior Triangle of Neck

cricothyroid    arch of the cricoid         inferior border of the    draws the thyroid        external branch of          this is the only intrinsic
                cartilage                   thyroid cartilage         cartilage forward,       superior laryngeal nerve,   muscle of the larynx that
                                                                      lengthening the vocal    a branch of the vagus       is not supplied by the
                                                                      ligaments                nerve (X)                   recurrent laryngeal n.;
                                                                                                                           ALL other laryngeal
                                                                                                                           muscles are innervated
                                                                                                                           by recurrent laryngeal
                                                                                                                           nerve, via its inferior
                                                                                                                           laryngeal branch
platysma        fascia overlying the        inferior border of        draws corners of mouth facial nerve (VII),           (Greek, platysma = flat
                pectoralis major and        mandible and skin of      down; aids in depression cervical branch             plate)
                deltoid muscles             lower face                of the mandible

digastric       anterior belly: digastric   body of hyoid via fibrous elevates hyoid;          anterior belly: mylohyoid forms two sides of the
                fossa of mandible;          loop over intermediate    depresses mandible       nerve, from mandibular submandibular triangle
                posterior belly: mastoid    tendon                                             division of trigeminal
                notch of temporal bone                                                         nerve (V); posterior belly:
                                                                                               facial nerve (VII)

stylohyoid      posterior border of         splits around              elevates and retracts   facial nerve (VII)   facial nerve innervates
                styloid process             intermediate tendon of     hyoid                                        both stylohyoid and
                                            digastric to insert on the                                              posterior belly of
                                            body of the hyoid bone                                                  digastric shortly after
                                                                                                                    exiting from the
                                                                                                                    stylomastoid foramen
mylohyoid       mylohyoid line of        midline raphe and body elevates hyoid bone and mylohyoid nerve from        the nerve to mylohyoid
                mandible                 of hyoid bone              tongue; depresses    inferior alveolar nerve, a also innervates anterior
                                                                    mandible             branch of mandibular       belly of digastric m.
                                                                                         division of trigeminal
                                                                                         nerve (V)
omohyoid        inferior belly: upper    inferior belly:            depresses/stabilizes ansa cervicalis            the intermediate tendon
                border of scapula medial intermediate tendon;       hyoid bone                                      of omohyoid is tethered
                to scapular notch;       superior belly: lower                                                      to the clavicle by a
                superior belly:          border of hyoid lateral to                                                 fascial sling
                intermediate tendon      sternohyoid insertion
sternohyoid     posterior surfaces of    lower border of hyoid      depresses/stabilizes ansa cervicalis            sternohyoid overlies
                manubrium and sternal bone, medial to               hyoid bone                                      sternothyroid and
                end of clavicle          omohyoid insertion                                                         thyrohyoid
sternothyroid   posterior surface of     oblique line of thyroid    depresses/stabilizes ansa cervicalis            sternothyroid lies deep to
                manubrium below          cartilage                  hyoid bone                                      sternohyoid
                sternohyoid origin
                                                             Anterior Triangle of Neck
thyrohyoid                 oblique line of thyroid   lower border of hyoid         elevates larynx;         ansa cervicalis (via        thyrohyoid lies deep to
                           cartilage                 bone                          depresses/stabilizes     fibers running with         the sternohyoid
                                                                                   hyoid bone               hypoglossal nerve that
                                                                                                            leave XII distal to the
                                                                                                            superior limb of ansa)
sternocleidomastoid        sternal head: anterior    mastoid process and           draws mastoid process spinal accessory nerve         carotid sheath structures
                           surface of manubrium;     lateral 1/2 of superior       down to same side; turns (XI), with sensory supply   lie deep to it
                           clavicular head: medial   nuchal line                   chin up toward opposite from C2 & C3 (for
                           1/3rd of clavicle                                       side                     proprioception)


                                                                         Nerves
          Nerve                     Source                    Branches                         Motor                   Sensory                   Notes
cervical plexus            ventral primary rami of   brs. to: longus colli &       longus colli & capitis,    skin of neck              close association of
                           C1-C4 spinal nerves       capitis,                      rectus capitis anterior & anterolaterally; skin of   supraclavicular nn. to
                                                     sternocleidomastoid,          lateralis, infrahyoid mm., ear & behind ear          phrenic n. results in pain
                                                     trapezius, levator            thyrohyoid, geniohyoid,                              from diaphragm referred
                                                     scapulae, scalenus            diaphragm                                            to shoulder (Latin,
                                                     medius, rectus capitis                                                             plexus = a braid)
                                                     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.

transverse cervical        cervical plexus (C2&C3)                                                            skin of neck anteriorly

supraclavicular,           cervical plexus (C3&C4)                                                            skin of root of neck &
intermediate                                                                                                  upper chest near mid-
                                                                                                              clavicle
supraclavicular, lateral   cervical plexus (C3&C4)                                                            skin of root of neck &    pain from respiratory
                                                                                                              upper shoulder            diaphragm is referred to
                                                                                                                                        the shoulder
supraclavicular, medial    cervical plexus (C3&C4)                                                            skin of root of neck&
                                                                                                              upper chest anteriorly
great auricular            cervical plexus (C2&C3) mastoid; auricular                                         skin of ear & below ear
                                                         Anterior Triangle of Neck

occipital, lesser   cervical plexus (C2)                                                                  skin behind ear          arises from a ventral
                                                                                                                                   primary ramus
ansa cervicalis     superior root (C1&C2) & to infrahyoid muscles            omohyoid, sternohyoid,                                superior & inferior roots
                    inferior root (C2&C3) of                                 sternothyroid, thyrohyoid,                            also known as anterior &
                    ansa cervicalis                                          geniohyoid                                            posterior roots (Latin,
                                                                                                                                   ansa = handle or loop)
accessory           cranial root: nucleus        cranial root joins vagus; GSE:                                                    also known as: CN XI,
                    ambiguus; spinal root:       spinal root ascends       sternocleidomastoid and                                 11th cranial nerve;
                    spinal nucleus of upper      through foramen           trapezius mm.                                           passes through jugular
                    cervical spinal cord         magnum                                                                            foramen; accessory n. is
                                                                                                                                   motor only;
                                                                                                                                   proprioceptive fibers
                                                                                                                                   reach
                                                                                                                                   sternocleidomastoid via
                                                                                                                                   C2&C3 and trapezius via
                                                                                                                                   C3&C4 (subtrapezial
                                                                                                                                   plexus)
hypoglossal         medulla: hypoglossal         branches of C1 carried      intrinsic and extrinsic                               also known as: CN XII,
                    nucleus                      by this nerve are not       muscles of the tongue                                 12th cranial nerve;
                                                 considered to be            (except palatoglossus                                 passes through the
                                                 branches of the             m.)                                                   hypoglossal canal;
                                                 hypoglossal nerve                                                                 superior root of ansa
                                                                                                                                   cervicalis travels with the
                                                                                                                                   hypoglossal n.
vagus               medulla: dorsal nucleus      auricular br., pharyngeal   SVE: intrinsic muscles of    GSA: skin of external    also known as: CN X,
                    (GVA & GVE                   br., superior laryngeal,    larynx, pharynx (except      auditory meatus; GVA:    10th cranial nerve;
                    preganglionic                superior & inferior         stylopharyngeus), &          viscera of head, neck,   passes through jugular
                    parasympathetic) from        cervical cardiac brs.,      palate (except tensor veli   thorax & abdomen         foramen; (Latin,vagus =
                    inferior ganglion, nucleus   recurrent laryngeal,        palatini); GVE: smooth       proximal to splenic      wanderer, because of its
                    ambiguus (SVE); spinal       thoracic cardiac brs.,      muscle of respiratory        flexure; SVA: taste to   wide distribution to the
                    trigeminal nucleus (GSA)     brs. to pulmonary           tree & gut (proximal to      epiglottis               body cavities)
                    from superior ganglion;      plexus, esophageal          splenic flexure), heart;
                    nucleus solitarius (SVA)     plexus, anterior &          secretomotor: mucous
                    from inferior ganglion       posterior vagal trunks      glands of larynx,
                                                                             respiratory tree, pharynx
                                                                             & gut, digestive glands
                                                          Anterior Triangle of Neck
cardiac                  vagus (X); cervical                                 heart (parasympathetic: heart, bronchial tree &     vagus has 2 (superior &
                         sympathetic trunk                                   decreases rate & force lungs                        inferior) cervical cardiac
                                                                             of contraction;                                     brs. & 1 or more thoracic
                                                                             sympathetic: increases                              br.; cervical sympathetic
                                                                             rate & force of                                     trunk usually gives 3
                                                                             contraction); bronchial                             (superior, middle &
                                                                             tree & lungs via                                    inferior) cardiac brs.
                                                                             pulmonary plexus

sympathetic chain        preganglionic             postganglionic            dilator pupillae m.;    pain from viscera           located parallel & lateral
ganglia, cervical        sympathetic via           sympathetic via gray      vascular smooth muscle;                             to vertebral bodies in
                         ascending fibers from T1- rami communicans to       arrector pili muscles &                             neck; there are no white
                         T5                        cervical spinal nn.;      sweat glands of head                                rami communicans at
                                                   internal & external       and neck; heart & lungs                             cervical levels
                                                   carotid nn.; cervical
                                                   cardiac brs.
cervicofacial division   facial (VII)              buccal, marginal          muscles of lower part of                           usually forms a loop by
                                                   mandibular, cervical      face, platysma                                     communication anteriorly
                                                                                                                                with temporofacial
                                                                                                                                division
mylohyoid                inferior alveolar                                   mylohyoid, anterior belly                          arises near lingula of
                                                                             of digastric                                       mandible
recurrent laryngeal      vagus (X)                esophageal brs.,           upper esophagus, lower      upper esophagus, lower right recurrent loops
                                                  tracheal brs., cardiac     pharynx, laryngeal ms.      pharynx, larynx below  posteriorly around right
                                                  brs., pharyngeal brs.,     (except                     vocal folds, GVA from  subclavian a.; left
                                                  inferior laryngeal n.      cricopharyngeus);           heart                  recurrent loops
                                                                             smooth muscle of                                   posteriorly around aortic
                                                                             trachea; secretomotor to                           arch & ligamentum
                                                                             mucous glands in upper                             arteriosum; inferior
                                                                             esophagus, lower                                   laryngeal br. supplies all
                                                                             pharynx, larynx below                              intrinsic muscles of the
                                                                             vocal fold, trachea;                               larynx EXCEPT
                                                                             cardiac muscle of heart                            cricothyroid m.
                                                                             (slows rate, decreases
                                                                             force of contraction)

superior laryngeal       vagus (X)                internal & external brs.   cricothyroid, inferior  mucous lining of larynx     external br. supplies
                                                                             pharyngeal constrictor, above vocal folds           cricothyroid m.; all other
                                                                             secretomotor to mucous                              intrinsic muscles of the
                                                                             glands of larynx above                              larynx are supplied by
                                                                             vocal folds                                         the recurrent laryngeal
                                                                                                                                 nerve
                                                                Anterior Triangle of Neck



inferior laryngeal         recurrent laryngeal br. of                               all muscles of larynx     mucous lining of larynx   continuous with
                           vagus (X)                                                except cricothyroid:      below vocal fold          recurrent laryngeal at
                                                                                    thyroarytenoid, oblique &                           inferior border of
                                                                                    transverse arytenoid,                               cricopharyngeus
                                                                                    posterior & lateral
                                                                                    cricoarytenoid,
                                                                                    aryepiglottic,
                                                                                    thyroepiglottic, vocalis;
                                                                                    secretomotor to mucous
                                                                                    glands of larynx below
                                                                                    vocal fold
to carotid body            vagus (X) &                                              chemoreception (blood
                           glossopharyngeal (IX)                                    pH) in carotid body;
                                                                                    blood pressure
                                                                                    recerptors in carotid
                                                                                    sinus; both located near
                                                                                    bifurcation of common
                                                                                    carotid a.
carotid plexus, external   superior cervical             distributes along external vascular smooth muscle,                             postganglionic
                           ganglion of the               carotid artery brs.        arrector pili muscles,                              sympathetic nerve fibers
                           sympathetic trunk, via                                   sweat glands of face &                              use arteries as roadways
                           external carotid n.                                      upper neck                                          to enter the head and
                                                                                                                                        neck (Latin, plexus = a
                                                                                                                                        braid)
carotid plexus, internal   superior cervical             most distribute along the   vascular smooth muscle                             postganglionic
                           ganglion of sympathetic       internal carotid artery     of brain, orbit, forehead,                         sympathetic nerve fibers
                           trunk, via internal carotid   brs., although deep         upper nasal cavity;                                use arteries as roadways
                           n.                            petrosal n. is an           arrector pili muscles of                           to enter the head and
                                                         exception                   forehead & ant. scalp;                             neck (Latin, plexus = a
                                                                                     sweat glands of                                    braid)
                                                                                     forehead; dilator pupillae



                                                              Arteries
          Artery                    Source                      Branches                      Supply                   Notes
                                                             Anterior Triangle of Neck
subclavian             brachiocephalic (right),      1st part: vertebral,          neck, spinal cord, thyroid   ant. scalene muscle
                       aortic arch (left)            thyrocervical trunk,          gland & larynx, shoulder,    passes anterior to
                                                     internal thoracic; 2nd        chest muscles, upper         subclavian, dividing it
                                                     part: costocervical trunk;    limb                         into 3 parts
                                                     3rd part: dorsal scapular
                                                     (70%); axillary a. is the
                                                     continuation at lat.
                                                     border of rib 1
common carotid         brachiocephalic trunk         external & internal           most of head & upper         common carotid a.
                       (right), aortic arch (left)   carotid (terminal brs.)       neck                         bifurcates at the level of
                                                                                                                the superior border of
                                                                                                                the thyroid cartilage;
                                                                                                                carotid sinus & body
                                                                                                                located at bifurcation
internal carotid       common carotid                none in the neck; in the      brain, eye, forehead         primary blood supply to
                                                     head: ophthalmic, post.                                    the brain; anastomoses
                                                     communicating, ant. &                                      with vertebral aa.
                                                     middle cerebral (terminal
                                                     brs.)
external carotid       common carotid                superior thyroid,             upper neck, face & scalp primary blood supply to
                                                     ascending pharyngeal,                                  face & superficial head
                                                     lingual, facial, occipital,
                                                     post. auricular, maxillary
                                                     & superficial temporal
                                                     (terminal brs.)
superior thyroid       external carotid              infrahyoid br.,               thyroid gland, upper
                                                     sternocleidomastoid br.,      larynx, infrahyoid
                                                     sup. laryngeal,               muscles,
                                                     cricothyroid br., ant.,       sternocleidomastoid
                                                     post. & lat. glandular brs.

ascending pharyngeal   external carotid              pharyngeal brs., inf.         pharynx                      arises from the medial
                                                     tympanic, post.                                            side of the external
                                                     meningeal                                                  carotid a. close to the
                                                                                                                birfurcation
lingual                external carotid              suprahyoid br., dorsal        tongue, suprahyoid           (Latin, lingula = tongue)
                                                     lingual brs., deep lingual,   muscles, palatine tonsil
                                                     sublingual
occipital              external carotid              sternocleidomastoid           lateral & post. neck,        anastomoses with deep
                                                     brs., auricular br.,          post. scalp                  cervical; joins greater
                                                     mastoid br., descending                                    occipital nerve
                                                     br., occipital brs.                                        posteriorly
                                                        Anterior Triangle of Neck



facial                external carotid         ascending palatine a.,        lower part of palatine    its angular branch
                                               tonsilar br., submental       tonsil, submandibular     anastomoses with the
                                               a., sup. & inf. labial as.,   gland, facial muscles &   ophthalmic a.
                                               lat. nasal br., angular a.    fascia

submental             facial                                                 muscles, skin & fascia
                                                                             under chin,
                                                                             submandibular gland
inferior thyroid      thyrocervical trunk      ascending cervical,           thyroid gland, lower
                                               inferior laryngeal,           larynx, upper trachea &
                                               esophageal brs.,              esophagus, neck
                                               tracheal brs., glandular      muscles
                                               brs.
thyroidea ima         brachiocephalic a. or    no named branches            isthmus of thyroid gland, present in 10% of
                      aortic arch                                           upper trachea             individuals; clinically
                                                                                                      significant because it is a
                                                                                                      midline artery in the
                                                                                                      region of tracheostomy;
                                                                                                      ima means "lowest"
posterior auricular   external carotid         stylomastoid br.,            part of external ear,
                                               auricular br., occipital br. scalp & deeper
                                                                            structures posterior to
                                                                            ear
inferior laryngeal    inferior thyroid                                      lower larynx internally
superior laryngeal    superior thyroid                                      upper larynx internally


                                                       Veins
           Vein                Tributaries            Drains Into                Region Drained                 Notes
posterior auricular                            unites with post. div. of     behind ear                connects with occipital v.
                                               retromandibular to form                                 behind ear
                                               external jugular
common facial         union of ant. div. of    internal jugular              face & anterior scalp
                      retromandibular & facial
anterior jugular      submental,               external jugular              anterior neck             (Latin, jugulum = throat)
                      communicating                                          superficially
                                                       Anterior Triangle of Neck

external jugular   formed by the union of      subclavian v.              head & neck, shoulder       (Latin, jugulum = throat)
                   the retromandibular &
                   posterior auricular vv.;
                   tributaries: posterior
                   external jugular,
                   transverse cervical,
                   suprascapular, anterior
                   jugular
internal jugular   formed by the union of      brachiocephalic v.         brain & skull, face,        largest vein of the nead
                   the sigmoid & inferior                                 viscera of neck             and neck (Latin, jugulum
                   petrosal sinuses;                                                                  = throat)
                   tributaries: pharyngeal
                   vv.; lingual, common
                   facial,
                   sternocleidomastoid,
                   superior & middle thyroid
                   vv.
retromandibular    formed by the union of      anterior & posterior        side of head & scalp;      contained within the
                   the superficial temporal    divisions of                deep face                  parotid gland
                   & maxillary vv.             retromandibular; anterior
                                               division unites with facial
                                               to form common facial,
                                               posterior division unites
                                               with posterior auricular
                                               to form external jugular

superior thyroid   superior laryngeal v.       internal jugular v.        superior portion of         cross the common
                                                                          thyroid gland and           carotid a.
                                                                          surrounding structures
middle thyroid                                 internal jugular v.        thyroid gland laterally
inferior thyroid                               left and right             thyroid gland inferiorly
                                               brachiocephalic vv.
thyroidea ima                                  left brachiocephalic vein inferior portion of thyroid an occasional branch
                                                                         gland                       formed by the union of
                                                                                                     the left and right inferior
                                                                                                     thyroid vv.; a midline
                                                                                                     structure which is in
                                                                                                     danger during
                                                                                                     tracheostomy
                                                          Posterior Triangle of Neck


                           Osteology
        Bone/Cartilage         Description                  Notes
                                                  it is the broadest,
                                                  shortest and widest of
                                                  the ribs; the scalene
                                                  tubercle marks its
                                                  superior surface and is
rib 1                    the most cephalic rib    an elevation between
                                                  grooves for the
                                                  subclavian vein & artery;
                                                  the scalene tubercle is
                                                  the attachment site of
                                                  the scalenus anterior m.
                                                  cervical vertebrae have
                                                  the features of the
                                                  typical vertebra plus all
                                                  have transverse
                                                  foramina (for passage of
                                                  the vertebral artery); C2-
                         the seven vertebrae of
cervical vertebrae                                C6 have bifid spinous
                         the neck
                                                  processes; cervical
                                                  vertebrae have relatively
                                                  small bodies; several
                                                  cervical vertebra are
                                                  named: atlas, axis,
                                                  vertebra prominens

                                                                      Muscles
           Muscle                 Origin                  Insertion                      Action                   Innervation                  Notes
                                                                                                                                     a muscle of inspiration;
                                                                                                                                     anterior scalene inserts
                         anterior tubercles of                                 elevates first rib; flexes                            behind the subclavian
                                                 scalene tubercle of first
scalene, anterior        transverse processes of                               and laterally bends the      brachial plexus, C5-C7   vein, and anterior to the
                                                 rib
                         vertebrae C3-C6                                       neck                                                  subclavian artery and
                                                                                                                                     roots of the brachial
                                                                                                                                     plexus
                                                         Posterior Triangle of Neck



                                                                                                                                     a muscle of respiration
                                                                                                                                     (inspiratory); also called
                      posterior tubercles of the                            elevates first rib; flexes
                                                 upper surface of first rib                                                          scalenus medius;
scalene, middle       transverse processes of                               and laterally bends the       brachial plexus, C3-C8
                                                 behind subclavian artery                                                            penetrated by the dorsal
                      vertebrae C2-C7                                       neck
                                                                                                                                     scapular n. and long
                                                                                                                                     thoracic n.
                      posterior tubercles of the                           elevates second rib;                                      a muscle of respiration
                                                 lateral surface of second
scalene, posterior    transverse processes of                              flexes and laterally           brachial plexus, C7-C8     (inspiratory); the longest
                                                 rib
                      vertebrae C5-C7                                      bends the neck                                            of the scalene muscles

                      sternal head: anterior                                   draws mastoid process      spinal accessory nerve
                                                 mastoid process and
                      surface of manubrium;                                    down to same side; turns   (XI), with sensory supply carotid sheath structures
sternocleidomastoid                              lateral 1/2 of superior
                      clavicular head: medial                                  chin up toward opposite    from C2 & C3 (for         lie deep to it
                                                 nuchal line
                      1/3rd of clavicle                                        side                       proprioception)

                                                                     Nerves
         Nerve                 Source                    Branches                        Motor                     Sensory                     Notes
                                                 brs. to: longus colli &
                                                 capitis,
                                                 sternocleidomastoid,
                                                 trapezius, levator
                                                 scapulae, scalenus
                                                 medius, rectus capitis
                                                 anterior & lateralis:         longus colli & capitis,                               close association of
                                                 superior & inferior root of   rectus capitis anterior & skin of neck                supraclavicular nn. to
                      ventral primary rami of
cervical plexus                                  ansa cervicalis, n. to        lateralis, infrahyoid mm., anterolaterally; skin of   phrenic n. results in pain
                      C1-C4 spinal nerves
                                                 thyrohyoid, n. to             thyrohyoid, geniohyoid, ear & behind ear              from diaphragm referred
                                                 geniohyoid, lesser            diaphragm                                             to shoulder
                                                 occipital, great auricular,
                                                 transverse cervical,
                                                 supraclavicular nn.
                                                 (medial, intermediate &
                                                 lateral), contribution to
                                                 phrenic n.
                                                        Posterior Triangle of Neck


                                                                                                                                   also known as: CN XI,
                                                                                                                                   11th cranial nerve;
                                                                                                                                   passes through jugular
                                                                                                                                   foramen; accessory n. is
                    cranial root: nucleus        cranial root joins vagus;
                                                                           GSE:                                                    motor only;
                    ambiguus; spinal root:       spinal root ascends
accessory                                                                  sternocleidomastoid and                                 proprioceptive fibers
                    spinal nucleus of upper      through foramen
                                                                           trapezius mm.                                           reach
                    cervical spinal cord         magnum
                                                                                                                                   sternocleidomastoid via
                                                                                                                                   C2&C3 and trapezius via
                                                                                                                                   C3&C4 (subtrapezial
                                                                                                                                   plexus)


                                                                             SVE: intrinsic muscles of
                    medulla: dorsal nucleus      auricular br., pharyngeal   larynx, pharynx (except
                    (GVA & GVE                   br., superior laryngeal,    stylopharyngeus), &                                   also known as: CN X,
                                                                                                          GSA: skin of external
                    preganglionic                superior & inferior         palate (except tensor veli                            10th cranial nerve;
                                                                                                          auditory meatus; GVA:
                    parasympathetic) from        cervical cardiac brs.,      palatini); GVE: smooth                                passes through jugular
                                                                                                          viscera of head, neck,
                    inferior ganglion, nucleus   recurrent laryngeal,        muscle of respiratory                                 foramen; vagus means
vagus                                                                                                     thorax & abdomen
                    ambiguus (SVE); spinal       thoracic cardiac brs.,      tree & gut (proximal to                               "wanderer" in reference
                                                                                                          proximal to splenic
                    trigeminal nucleus (GSA)     brs. to pulmonary           splenic flexure), heart;                              to its extensive
                                                                                                          flexure; SVA: taste to
                    from superior ganglion;      plexus, esophageal          secretomotor: mucous                                  distribution to the body
                                                                                                          epiglottis
                    nucleus solitarius (SVA)     plexus, anterior &          glands of larynx,                                     cavities
                    from inferior ganglion       posterior vagal trunks      respiratory tree, pharynx
                                                                             & gut, digestive glands


                                                                                                          pericardium;
                                                                                                                                   crosses the anterior
                    ventral primary rami of                                                               mediastinal,
phrenic                                          pericardial brs.            diaphragm                                             surface of the anterior
                    C3-C5 (cervical plexus)                                                               diaphragmatic & costal
                                                                                                                                   scalene m.
                                                                                                          pleura
                                              postganglionic
                                              sympathetic via gray           dilator pupillae m.;                                  located parallel & lateral
                    preganglionic
                                              rami communicans to            vascular smooth muscle;                               to vertebral bodies in
sympathetic chain   sympathetic via
                                              cervical spinal nn.;           arrector pili muscles & pain from viscera             neck; there are no white
ganglia, cervical   ascending fibers from T1-
                                              internal & external            sweat glands of head                                  rami communicans at
                    T5
                                              carotid nn.; cervical          and neck; heart & lungs                               cervical levels
                                              cardiac brs.
                                                          Posterior Triangle of Neck
                                                                            upper esophagus, lower
                                                                            pharynx, laryngeal ms.                            right recurrent loops
                                                                            (except                                           posteriorly around right
                                                                            cricopharyngeus);                                 subclavian a.; left
                                                                            smooth muscle of                                  recurrent loops
                                                   esophageal brs.,                                    upper esophagus, lower
                                                                            trachea; secretomotor to                          posteriorly around aortic
                                                   tracheal brs., cardiac                              pharynx, larynx below
recurrent laryngeal   vagus (X)                                             mucous glands in upper                            arch & ligamentum
                                                   brs., pharyngeal brs.,                              vocal folds, GVA from
                                                                            esophagus, lower                                  arteriosum; inferior
                                                   inferior laryngeal n.                               heart
                                                                            pharynx, larynx below                             laryngeal br. supplies all
                                                                            vocal fold, trachea;                              intrinsic muscles of the
                                                                            cardiac muscle of heart                           larynx EXCEPT
                                                                            (slows rate, decreases                            cricothyroid m.
                                                                            force of contraction)

                                                   dorsal scapular, long
                                                                                                                                plexus is a latin word
                                                   thoracic, n. to
                                                                                                                                meaning "braid"; axons
                                                   subclavius,
                                                                                                                                from spinal cord levels
                                                   suprascapular, lateral &
                                                                                                                                C5-T1 are mixed
                                                   medial pectoral, medial
                                                                                                                                (braided) in the brachial
                      ventral primary rami of      brachial & antebrachial muscles of upper limb,
brachial plexus                                                                                        skin of upper limb       plexus and repackaged
                      C5-8 & T1                    cutaneous, upper,        excluding trapezius
                                                                                                                                into terminal branches
                                                   middle & lower
                                                                                                                                so that each branch
                                                   subscapular,
                                                                                                                                contains axons from
                                                   musculocutaneous,
                                                                                                                                several spinal cord
                                                   ulnar, median, axillary,
                                                                                                                                levels
                                                   radial
                                                                            rhomboid major & minor;                             passes through scalenus
dorsal scapular       brachial plexus (C5)                                                          no cutaneous branches
                                                                            levator scapulae                                    medius
                                                                                                                                located on superficial
                                                                                                                                surface of serratus
                                                                                                                                anterior; lesion causes
long thoracic         brachial plexus (C5-C7)                               serratus anterior          no cutaneous branches    scapular winging, hence
                                                                                                                                the saying "C5, 6, & 7
                                                                                                                                keep the wings from
                                                                                                                                heaven"
                                                                                                                                passes through scapular
                      superior trunk of brachial                            supraspinatus,                                      notch inferior to the
suprascapular                                                                                          no cutaneous branches
                      plexus (C5-C6)                                        infraspinatus                                       superior transverse
                                                                                                                                scapular ligament


                                                        Arteries
                                                            Posterior Triangle of Neck
            Artery              Source                      Branches                      Supply                        Notes
                                                    1st part: vertebral,
                                                    thyrocervical trunk,
                                                    internal thoracic; 2nd       neck, spinal cord, thyroid   ant. scalene muscle
                      brachiocephalic (right),      part: costocervical trunk;   gland & larynx, shoulder,    passes anterior to
subclavian
                      aortic arch (left)            3rd part: dorsal scapular    chest muscles, upper         subclavian, dividing it
                                                    (70%); axillary a. is the    limb                         into 3 parts
                                                    continuation at lat.
                                                    border of rib 1
                                                                                                              common carotid a.
                                                                                                              bifurcates at the level of
                      brachiocephalic trunk         external & internal          most of head & upper         the superior border of
common carotid
                      (right), aortic arch (left)   carotid (terminal brs.)      neck                         the thyroid cartilage;
                                                                                                              carotid sinus & body
                                                                                                              located at bifurcation
                                                    none in the neck; in the
                                                    head: ophthalmic, post.                                   primary blood supply to
internal carotid      common carotid                communicating, ant. &       brain, eye, forehead          the brain; anastomoses
                                                    middle cerebral (terminal                                 with vertebral aa.
                                                    brs.)
                                                    superior thyroid,
                                                    ascending pharyngeal,
                                                    lingual, facial, occipital,                               primary blood supply to
external carotid      common carotid                                            upper neck, face & scalp
                                                    post. auricular, maxillary                                face & superficial head
                                                    & superficial temporal
                                                    (terminal brs.)
                                                    spinal brs., muscular                                     anastomoses with
                                                    brs., ant. spinal, post. inf.                             internal carotid in
                                                    cerebellar, medullary         deep neck, cervical         cerebral arterial circle (of
vertebral             subclavian (1st part)
                                                    brs., meningeal brs.,         spinal cord, hindbrain      Willis); courses through
                                                    basilar (fusion of paired                                 transverse foramina of
                                                    vertebrals)                                               vertebrae C1-C6
                                                    inferior thyroid,
                                                                                 lower neck, posterior
thyrocervical trunk   subclavian, 1st part          transverse cervical,                                      a short thick trunk
                                                                                 shoulder, thyroid gland
                                                    suprascapular
                                                    ascending cervical,
                                                                                 thyroid gland, lower
                                                    inferior laryngeal,
                                                                                 larynx, upper trachea &
inferior thyroid      thyrocervical trunk           esophageal brs.,
                                                                                 esophagus, neck
                                                    tracheal brs., glandular
                                                                                 muscles
                                                    brs.
inferior laryngeal    inferior thyroid                                           lower larynx internally
                                                           Posterior Triangle of Neck

                                                    ascending cervical,
                                                                                thyroid gland, lower
                                                    inferior laryngeal,
                                                                                larynx, upper trachea &
inferior thyroid      thyrocervical trunk           esophageal brs.,
                                                                                esophagus, neck
                                                    tracheal brs., glandular
                                                                                muscles
                                                    brs.
                                                                                trapezius muscle &         may give off the dorsal
transverse cervical   thyrocervical trunk           muscular
                                                                                surrounding muscles        scapular a. (30%)
                                                                                                           anastomoses with
                                                                                supraspinatus &
                                                                                                           circumflex scapular,
suprascapular         thyrocervical trunk           muscular                    infraspinatus, shoulder
                                                                                                           dorsal scapular & deep
                                                                                joint
                                                                                                           br. of transverse cervical
                                                                            anterior chest wall,
                                                    anterior intercostal aa.,                              commonly called
internal thoracic     subclavian, 1st part          musculophrenic,         anterior portion of            "internal mammary" in
                                                    superior epigastric     intercostal spaces             clinical settings
                                                                            muscles of neck
                                                                                                           located between anterior
                                                    deep cervical & supreme posteriorly; first 2
costocervical trunk   subclavian, 2nd part                                                                 & middle scalene
                                                    intercostal             posterior intercostal
                                                                                                           muscles
                                                                            spaces
                                                                                                           anasotmoses with
                                                                                                           suprascapular &
                                                                                levator scapulae,
                      subclavian, end of 3rd                                                               subscapular aa.; a
dorsal scapular                                     muscular                    rhomboideus major &
                      part                                                                                 branch of the transverse
                                                                                minor mm.
                                                                                                           cervical a. in 30% of
                                                                                                           cases
                                                                                 part of external ear,
                                                    stylomastoid br.,            scalp & deeper
posterior auricular   external carotid
                                                    auricular br., occipital br. structures posterior to
                                                                                 ear

                                                           Veins
           Vein              Tributaries                   Drains Into              Region Drained                  Notes
                      union of subclavian &
                      internal jugular;                                                                    at its origin, left
                                                    left & right
                      vertebral, thymic, inferior                                                          brachiocephalic receives
                                                    brachiocephalic vv. unite head, neck, upper limb,
brachiocephalic       thyroid, internal thoracic,                                                          thoracic duct, right
                                                    to form superior vena     anterior chest wall
                      1st post. intercostal, left                                                          receives right lymphatic
                                                    cava
                      superior intercostal (to                                                             duct
                      left brachiocephalic)
                                                    Posterior Triangle of Neck




                   formed by the union of
                   the retromandibular &
                   posterior auricular vv.;
                   tributaries: posterior
external jugular                             subclavian v.        head & neck, shoulder
                   external jugular,
                   transverse cervical,
                   suprascapular, anterior
                   jugular
                   formed by the union of
                   the sigmoid & inferior
                   petrosal sinuses;
                   tributaries: pharyngeal
                                                                  brain & skull, face,    largest vein of the nead
internal jugular   vv.; lingual, common      brachiocephalic v.
                                                                  viscera of neck         and neck
                   facial,
                   sternocleidomastoid,
                   superior & middle thyroid
                   vv.

				
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