NECK

Cervical Vertebrae

Typical C vertebrae are 3-6: body wider transverse than APSup surface concave, inf convex; foramen large; transverse process include transverse foramina for vertebral vessels; spinous processes are short and bifidC1: no spinous process or body; sup articular facets receive occipital condylesC2C7: long spinous process which isn’t bifid, large transverse processes, small transverse foramina

Hyoid Bone

Fascia

Superficial cervical fascia (subcutaneous): fatty; contains cutaneous nerves, blood, lymph vessels, superficial LN’s and platysma

Atlas C1 Axis C2

Lies at C3Attached by muscles to mandible, styloid process (stylohyoid ligs), thyroid cartilage (firmly bound), Manubrium and scapula; does NOT articulate with any other boneGreater horn attached to body by fibrocartilage in young, bone in oldLesser horn attached to body by fibrous cartilage, to greater horn by synovial jt

Regions

Platysma: broad thin sheet in subC tissue; supplied by cervical branch of CN VII; EJV (from angle of mandible to half way across clavicle) and cut nerves are deep to plarysma; attaches to inf border of mandible; fibres diverge anteriorly to leave gap over larynx and trachea

Deep cervical fascia: 3 layers; limit spread of infection1) Investing layer: most superficial; surrounds entire neck; splits

into superficial and deep layers to surround trapezius and SCM (CN XI, attach to cranial base, scapular spine, acromion and clavicle); suprasternal space between 2 layers sup to manubrium encloses ant jugular veins, jugular venous arch, fat, LN’s; attaches to sup nuchal line, mastoid processes, zygomatic arches, inf border mandible, hyoid, spinous processes, manubrium, clavicle, acromion and spine of scapula; forms fibrous capsule of parotid; forms stylomandibular ligament

2) Pretracheal layer: in ant neck; from hyoid to blend with fibrous pericardium; muscular part encloses infrahyoid muscles, visceral part encloses thyroid gland, trachea and oesophagus; continuous with buccopharyngeal fascia of pharynx and laterally with carotid sheathes; forms pulley through which intermediate tendon of digastric passes

3) Prevertebral layer: tubular sheath around vertebral column and muscles; blends with endothoracic fascia, fuses with ant longitudinal lig at T3; extends laterally as axillary sheath (axillary vessels and brachial plexus)

4) Carotid sheath: from cranial base to root of neck; contains common and in carotids, IJV, vagus nerve, deep cervical LN’s, carotid sinus nerve, sym nerve fibres; communicate with mediastinum

Retropharyngeal space: largest potential space, between prevertebral layer and buccopharyngeal fascia (of pretracheal); alar fascia forms subdivision (from carotid sheath to BP fascia in midline); closed by cranial base and carotid sheathes, opens into sup mediastinum

SCM Region

SCM: from lat surface mastoid process of temporal bone and lat half sup nuchal line (post to axis of atlantooccipital joint) sternal head (ant manibrium) and clavicular head (sup med 1/3 clavicle); nerve: CN XI motor, C2+3 painDivides neck into ant and lat; between these 2 triangles is SCM region; lesser supraclavicular fossa lies between 2 headsProduces movement at craniovertebral and cervical intervertebral jointsOther contents: sup part of EJV, greater auricular nerve, transverse cervical nerve, inf part of IJV

Posterior RegionTrapezius: med 1/3 sup nuchal line, ext occipital protuberance, nuchal ligament, spinous proceeses C7-T12, lumbar and sacral spinous processes lat 1/3 clavicle, acromion, spine of scapula; nerve: CN XI, C2-3 (pain and proprioception)Post to ant border of trapeziusOther contents: cut branches of post rami of cervical spinal nervesSuboccipital region: deep to sup part of posterior region

Lateral cervical region (Post triangle of neck): from post border of SCM to ant border of trapezius, base is middle 1/3 clavicle, apex is sup nuchal line of occipital bone, roof is investing layer, floor is prevertebral layer (overlying splenus capitis, levator scapulae, middle and post scaleneOccipital triangle: occipital artery (from ex carotid) appears at apex, crossed by spinal accessory nerve

Omoclavicular triangle: indicated by supraclavicular fossa; crossed by sup part of EJV; subclavian artery lies deep in it

Arteries: transverse cervical artery (subclavian thryrocervical trunk TCA), runs superficially and laterally across phrenic nerve and ant scalene muscle, then through branches of brachial plexus (branches to vasa nervorum), then deep to trapezius; superficial branch accompanies spinal accessory nerve (XI) under trapezius, deep branch runs ant to rhomboid as dorsal scapular arterysuprascapular artery (from thyrocervical trunk) passes inflat across ant scalene muscle and phrenic nerve crosses 3rd part of subclavian artery and cords of brachial plexus passes post to clavicle3rd part of subclavian: begins sup to clavicle, opposite lat border of ant scalene muscle as it passes out from under it lies on 1st rib; inf trunk of brachial plexus lies post to this

Veins:

EJV: begins near angle of mandible (by union of post division of retromandibular vein with post auricular vein) crosses SCM obliquely deep to platysma enters antinf part of lat cervical region terminates in subclavian vein

Subclavian: curves through inf part of lat cervical region; passes ant to ant scalene muscle and phrenic nerve unites with IJV and med border of ant scalene muscle; receives transverse cervical, suprascapular and ant jugular veins

Suprahyoid muscles: mylohyoid: from mylohyoid line of mandible to mylohyoid raphe and body of hyoid Geniohyoid: from inf mental spine of mandible to body of hyoid Stylohyoid: from styloid process of temporal bone to body of hyoid Digastric: from digastric fossa of mandible/mastoid notch of temporal bone to

intermediate tendon; has 2 bellies joined by tendon, a fibrous sling connects tendon to body and greater horn of hyoid

Infrahyoid muscles: superficial plane = sternohyoid: from Manubrium and medial end of clavicle to body of hyoid Omohyoid: from sup border of scapula near suprascapular notch to

inf border of hyoid; has sup and inf bellies connected by intermediate tendon

deep plane = sternothyroid: from post Manubrium to oblique line of thyroid cartilage thyrohyoid: from oblique line of thyroid to inf border of hyoid

Nerves: spinal accessory nerve (XI): passes deep to SCM enters lat cervical region 2/3 way up passes inferiorly on levator scapulae passes deep to trapezius 1/3 way upBrachial plexus: appear between ant and middle scalenes pass between 1st rib, clavicle and sup border of scapula (cervicoaxillary canal)Suprascapular nerve: arises from sup trunk branches to supraspinatus, infraspinatus, Glenohumeral jt

Ant Cervical RegionFrom median line of neck, to ant border of SCM; sup is in inf border of mandible, apex is jugular notch in Manubrium, roof is platysma, floor is pharynx larynx and thyroidDivided into 4 triangles:

1) Submental triangle: bounded inferiorly by hyoid, laterally by digastric muscles, floor is mylohyoid muscles which meet at median fibrous raphe, apex is mandibular symphysis; contains submental LN’s and veins that unite to form ant JV

2) Submandibular triangle: from inf border of mandible to bellies of digastric muscle, floor formed by mylohyoid and hypoglossus; contains submandibular gland and LN’s; contains hypoglossal nerve (XII), nerve to mylohyoid muscle, facial artery, submental artery

3) Carotid triangle: bounded by sup belly of omohyoid, post belly of digastric, ant border of SCM; contains common carotid artery (divides into int and ex at sup border of thyroid cartilage), carotid sinus (dilation of prox part of in carotid, innervated by carotid sinus nerve (IX) and vagus), carotid body (on med side of bifurcation; carotid sheath contains carotid arteries medially, IJV laterally, vagus nerve posteriorly, ansa cervicalis on antlat aspect of sheath, deep cervical nodes

4) Muscular triangle: bounded by sup belly of omohyoid, ant border of SCM, median plane of neck; contains infrahyoid muscles and viscera

5-Lingual: anterior; passes deep to hypoglossal nerve, stylohyoid, post belly of digastric, hyoglossus; bifurcates into deep lingual and sublingual arteries6-Facial: anterior; gives rise to ascending palatine artery and tonsillar branch; passes under digastric and stylohyoid muscle; supplies submandibular gland; gives rise to submental artery

Nerves: transverse cervical nerve (C2-3): ant cervical regionHypoglossal nerve (XII): enters submandibular triangle deep to post belly of digastric; passes between ex carotid and jugular vessels; gives off sup root of ansa cervicalis (C1)Glossopharyngeal (IX) and vagus (X): in submandibular and carotid triangles; X gives rise to pharyngeal, laryngeal and cardiac branches

Common carotid artery ascends within carotid sheath with IJV and vagus nerveIn carotid: begin at sup border of thyroid cartilage; prox part is site of carotid sinus, carotid body in cleft between in and ex carotids, enter cranium through carotid canals in petrous part of temporal bone

Ex carotid: runs to region between neck of mandible and lobule of auricle, embedded in parotid gland, divides into 2 branches – superficial temporal artery, maxillary artery. Branches:1-Ascending pharyngeal: medial, ascends on pharynx, branches to pharynx, prevertebral, middle ear, cranial meninges2-Occipital: posterior, passes posteriorly parallel to post belly of digastric in occipital groove in temporal bone, passes superficial to int carotid and CN IX-XI3-Posterior auricular: posterior, ascends between ex acoustic meatus and mastoid process; supplies parotid, fasvial nerve, temporal bone, auricle, scalp4-Sup thyroid: anterior, runs deep to infrahyoid muscles to reach thyroid gland; supplies infrahyoid muscles and SCM; gives off sup laryngeal artery

IJV: drains from brain, ant face, cervical viscera, deep muscles of neck; commences at jugular foramen in post cranial fossa as continuation of sigmoid sinus dilation at origin is superior bulb of IJV descends in carotid sheath (lies laterally in sheath), cervical sym trunk lies posterior to sheath passes deep to SCM, passes deep to gap between sternal and clavicular heads of muscles merges with subclavian vein post to sternal end of clavicle (inf bulb of IJV here, has a bicuspid valveBranches: inf petrosal sinus: enters sup bulb

Facial: enters at inf level of hyoid Lingual: empties at level of lingual artery Pharyngeal: at level of angle of mandible Sup and middle thyroid

Cervical Plexus

Motor branches: dorsal scapular nerve (C4-5): rhomboidsLong thoracic nerve (C5-7): serratus anteruirPhrenic nerve (C3-5): motor (diaphragm), sensation (diaphragm, pleura and pericardium), sym;

form at lat border of ant scalene at sup border of thyroid cartilage descends with IJV on L crosses ant to 1st part of subclavian artery, on R crosses ant to 2nd part of subclavian artery; both run post to subclavian vein and ant to int thoracic artery

Deep Structures of Neck

Lies antmedial to levator scapulae and middle scalene muscles, deep to SCMAnsa cervicalis: sup root descends from hypoglossal nerve; consists of fibres from C1-3; supplies infrahyroid muscles (eg. Omohyoid, sternothyroid, sternohyoid); thyrohyoid is only infrahyoid muscle not supplied by ansa cervicalisCutaneous branches: emerge around middle of post border of SCM; supply skin of neck, suplat thoracic wall, scalpC2 lesser occipital nerve: supplies skin of neck and scalp postsup to auricleC2-3 great auricular nerve: ascends across SCM to inf pole of parotid gland; supplies skin across parotid gland, mastoid process, auricleC2-3 transverse cervical nerve: ant cervical region, curves around middle of post border of SCM inf to great auricular nerve, crosses deep to EJV and platysmaC3-4 Supraclavicular nerve: skin of neck crossing clavicle and shoulder

AJV: arises near hyoid as continuation of superficial submandibular veins descends between ant median line and ant border of SCM runs post to SCM opens into EJV/subclavian, often unite across midline to form jugular venous arch in suprasternal spaceSubclavian vein: separated from artery by ant scalene muscle. Receives EJV. Unites with IJV to form BC.

Vagus nerve: leaves jugular foramen passes in post carotid sheath; cardiac branches convey presynaptic paraS and visceral afferent fibres to cardiac plexusR: passes ant to 1st subclavian and post to BC vein; recurrent laryngeal loops inf to R subclavian at T1-2 ascend in tracheoesophageal grooveL: descends between L common carotid and subclavian; recurrent laryngeal loops inf to AofA at T4-5

Phrenic nerve: formed at lat border of ant scalene, descend ant to ant scalene under IJV and SCM pass between subclavian arteries and veins

Sym trunks: have 3 cervical sym ganglia (sup, mid, inf may fuse with 1st thoracic ganglion to form cervicothoracic ganglion) send fibres via gray communicating branches (to cervical spinal nerves), cardiopulmonary splanchnic nerves (to thoracic viscera), cephalic arterial branches (to head and neck viscera); running in periarterial nerve plexuses.

Viscera of the Neck

Thyroid: lies deep to sternothyroid and sternohyoid; at C5-T1; lobes united by isthmus ant to 2nd + 3rd tracheal rings; surrounded by fibrous capsule; attached to cricoid cartilage; supplied by sup (from ex carotids, divides into ant and post branches) and inf (from thyrocervical trunks, run post to carotid sheath) thyroid arteries between fibrous capsule and fascial sheath; 10% have a thyroid ima artery from BC trunk; 3 pairs of thyroid veins (sup + mid IJV, inf BC); lymph prelaryngeal, pretracheal, paratracheal sup and inf deep cervical LN’s; nerves from cervical ganglia via cardiac periarterial plexuses

Parathyroid: lie on medpost thyroid external to capsule; sup and inf glands; most have 4; supplied by inf thyroid arteries usually; parathyroid veins drain into thyroid plexus of veins; nerves are vasomotor rather than secretomotor

Pharynx: from cranial base to inf border of cricoid cartilage anteriorly and to inf border of C6 posteriorly; widest at hyoid, narrowest inferiorly; palatine, lingual, tubal and pharyngeal tonsils from tonsillar ring

Ant vertebral muscles: longus colli, capitis, rectus capitis anterior, ant scalene. Lie post to rectopharyngeal space, medial to neurovascular planeLat vertebral muscles: rectus capitis lateralis, splenius capitis, levator scapulae, middle and posterior scalene muscles. Lie post to neurovascular plane, form floor of lat cervical region.

Brachiocephalic trunk covered anteriorly by R sternohyoid and sternothyroid musclesSubclavian arteries begin post to SC joint pass post to ant scalene, 3 parts of subclavian are relative to ant scalene, pleura and sym trunks lie post to 1st part arteries. Part 1: vertebral (ascends in pyramidal space between middle scalene and longus capitis deep to go through foramina C1-6 in groove on pst arch of atlas enters cranial cavity through foramen magnum branches to medulla, spinal cord, cerebellum both join to form basilar artery), int thoracic, thyrocervical (arises near medial border of ant scalene inf thyroid, suprascapular, transverse cervical, inf thyroid, ascending cervical)Part 2: costocervical trunk sup intercostal, deep cervicalPart 3: dorsal scapular artery (may be branch of transverse cervical) – passes laterally through brachial plexus, ant to middle scalene

1) Nasopharynx – sup to soft palate; lymphoid tissue forms incomplete tonsillar ring; pharyngeal tonsil in post wall, tubal tonsil near orifice of pharyngotympanic tube; vertical salpingopharyngeal fold extends inferiorly from medial end of pharyngotympanic tube, covers muscle, creates pharyngeal recess

2) Oropharynx – post to mouth; bounded by palatoglossal and palatopharyngeal arches laterally; contains palatine tonsils, do not fill tonsillar sinus between palatoglossal and palatopharyngeal arches in adults; tonsillar bed formed by superior constictor

a. Stage 1: voluntary, bolus pushed into oropharynx by tongue and soft palateb. Stage 2: involuntary; soft palate elevate, pharynx widened and shortened, suprahyoid and

longitudinal pharyngeal muscles contract, elevating larynxc. Stage 3: involuntary; sequential contraction of 3 constrictor muscles

3) Laryngopharynx – post to larynx; from sup border of epiglottis and pharyngoepiglottic folds to inf border cricoid cartilage; post and lat walls formed by superior, middle and inferior constrictors (supplied by pharyngeal branch of X, also ex and recurrent laryngeal nerve in latter 2), internally by palatopharyngeus, salpingopharyngeus (pharyngeal branch of X) and stylopharyngeus (IX); piriform fossa on either side of laryngeal inlet, separated by aryepiglottic fold, contains branches of int laryngeal and recurrent laryngeal nerves. Gaps to pass

a. Cranium and Sup constrictor: levator veli palatine, pharyngotympanic tube, ascending palatine artery pass

b. Sup and middle constrictors: stylopharyngeus, glossopharyngeal nerve, stylohyoid ligament

c. Middle and inf: int laryngeal nerve, sup laryngeal arteryd. Inf constrictor: recurrent laryngeal nerve, inf laryngeal artery

Vessels: tonsillar artery (branch of facial) – passes through sup constrictorExternal palatine vein – enters pharyngeal venous plexusTonsillar lymphatic vessels jugulodigastric node

Nerves: pharyngeal plexus – motor X (except stylopharyngeus XI and tensor veli palatine V3), sensory glossopharyngeal and maxillary

Larynx: C3-6; composed of 9 cartilagesThryoid: sup border lies at C4, laminae fuse anteriorly to form laryngeal prominence, with sup thyroid notch above and small inf thyroid notch’ post borders from sup and inf horns; sup attached to thyrohyoid membrane which form ligaments; inf horns articulate at cricothyroid jointsCricoid: thicker and stronger than thyroid; attaches to median cricothyroid and to cricotracheal ligament (to 1st tracheal ring)Arytenoid: paried, pyramidal, articulate with cricoid, apex attaches to aryepiglottic fold, post and lat cricoarytenoid muscles attached to muscular process

Cricoarytenoid joints – between bases of arytenoids cartilages and suplat surface of cricoid cartilage; vocal ligaments extend from thyroid cartilage anteriorly to vocal process of arytenoids cartilage posteriorly, they are the sup border of conus elasticus (lat parts of this membrane form lat cricothyroid ligaments, med parts blend with median CT lig), rima glottidis is opening between vocal folds

Epiglottic: post to root of tongue and hyoid, ant to laryngeal inlet, stalk is attached by thyroepiglottic ligament to thyroid cartilage, by hyoepiglottic ligament to hyoid; quadrangular membrane attaches to lat epiglottis and arytenoid, inf margin is vestibular membrane which forms vestibular fold, sup margin forms aryepiglottic ligament which forms foldCorniculate: small nodule in aryepiglottic ligament; attach to apex of arytenoidCuneiform: small nodule in aryepiglottic ligament; not attached to any other cartilageVestibular folds (false vocal cords) extends between thyroid and arytenoids, made up of vestibular ligaments

From laryngeal inlet to inf border of cricoid cartilage1) Laryngeal vestibule: between inlet and vestibular folds2) Middle part: between vestibular and vocal folds3) Laryngeal ventricle: laterally extend from middle part, saccule is blind pocket opening into each

ventricle4) Infraglottic cavity: vocal folds to inf border of cricoid cartilage

Laryngeal muscles Extrinsic: infrahyoids (depressors), suprahyoid (elevators)Intrinsic: mostly supplied by recurrent laryngeal nerve (X) except cricothyroid which is supplied by external laryngeal nerve (from sup laryngeal nerve)

Adductors and abductors; move focal cords; adductors – lat cricoarytenoid muscles, transverse and oblique arytenoids muscles; abductors – post cricoarytenoid musclesSphincters: lat cricoarytenoids, transverse and oblique arytenoids, aryepiglotticTensors: cricothryoidRelaxers: thyroarytenoid, vocalis

Arteries: laryngeal (from sup and inf thyroid); sup laryngeal accompanies int branch of sup laryngeal nerve through thyrohyoid membrane to supply int surface of larynx; inf laryngeal artery accompanies inf laryngeal nerve to supply mm and musclesVeins: sup laryngeal vein sup thyroid, inf laryngeal vein inf thyroidLymph: sup to vocal cords drain to sup deep cervical LN’s, inf drainto pretracheal/paratracheal LN’s inf deep cervical LN’sNerves: sup and inf laryngeal branches of vagus; sup from inf vagal ganglion and sup end of carotid triangle (int pierces with sup laryngeal artery to supply sensory to mm of middle cavity; ext descends post to sternothyroid muscle, piercing inf constrictor muscle, supply cricothyroid); inf from recurrent laryngeal nerve passes deep to inf constrictor muscle medial to lamina of thyroid cartilage – ant branch to lat cricothyroid, thyroarytenoid, vocalis, aryepiglottic, thyroepiglottic; post branch to post cricoarytenoid, transverse and oblique arytenoids

Trachea

Fibrocartilaginous tube surrounded by incomplete cartilaginous tracheal rings, deficient posteriorly, gap spanned by trachealis muscle; begins at C6 sternal angle (T4-5 IV disc)

OesophagusStriated muscle upper 1/3, smooth muscle lower 1/3, mix middle 1/3; begins at level of inf border of cricoid cartilage at C6; moves to L as it descends; recurrent laryngeal nerve runs in tracheoesophageal groove on either side of oesophagus; in contact with cervical pleura; lobes of thyroid gland and carotid sheaths laterally; thoracic duct adheres to L sideArteries: from inf thyroid arteriesVeins: from inf thyroid veinsLymph: to paratracheal and inf deep cervical LN’sNerves: somatic motor (recurrent laryngeal) and sensory to upper 1/2; paraS, sym and visceral sensory to lower 1/2

Lymphatics: superficial cervical inferior deep cervical (prelaryngeal, pretracheal, paratracehal, retropharyngeal) jugular lymphatic trunks join thoracic duct or R lymphatic duct. Thoracic duct passes on L side oesophagus arches laterally post to carotid sheath, ant to sym trunk and vertebral and subclavian arteries enters at venous angle. R jugular, subclavian and brachiomediastinal lymphatic trunks unite to form R lymphatic duct.