Common Carotid Artery :

Common Carotid Artery : • Origin :Rt.C.C.arise from brachiocephalic artery behind sternoclavicular j., left C.C. arise from arch of aorta in sup.mediastinum. • Termination : 2 terminal branches , external & internal carotid arteries at the upper border of thyroid cartilage (opposite C4 vertebra). • At point of bifurcation, it presents a carotid sinus and carotid body behind, ,they are innervated by glossopharyngeal N. , the sinus acts as presso-receptor(regulate blood pressure in cerebral arteries), but the body acts as a chemo-receptor (regulate respiration).

Common Carotid Artery : • It is embedded within the carotidsheath with internal j.v. + vagus N. Relations : • Anterolaterally : skin, fascia, sternomastoid, sternothyroid, sternohyoid & sup.belly of omohyoid. • Posteriorly : transverse processes of lower 4 cervical vertebrae + prevertebral Ms. (longus colli & longus capitis) + sympathetic trunk. • Medially : larynx, pharynx, trachea, esophagus & lobe of thyroid gland. • Laterally : internal J.V. + vagus nerve.

External Carotid Artery : • It supplies structres in neck, face,, scalp ,tounge & maxilla. • Origin :at superior border ofthyroid cartilage (at C4 vertebra), its pulsation can be felt. • It terminates in parotid gland behind neck of mandible by dividing into superficial temporal& maxillary arteries. • It lies at its beginning medial to Int.C.artery, then backward then laterally.

External Carotid Artery : • Relations :Antero-laterally (superficial relation) :1-skin, fascia. 2-it is crossed by hypoglossal N.,stylohyoid + post.belly of digastric, Medially (deep relation) :1-internal C. artery (above). 2-pharynx. 3- Stylopgaryngeus muscle , glosso-pharyngeal N. & pharyngeal branch of vagus. (structures between int.& ext. arteries)

Branches of External Carotid Artery : • Superior thyroid artery. • Ascending pharyngeal artery. • Lingual artery. • Facial artery. • Occipital artery. • Posterior auricular artery. • Superficial temporal artery. • Maxillary artery.

Branches of External Carotid Artery : • Superior thyroid artery : -it gives off a branch to sternomastoid & superior laryngeal artery , which pierces thyrohyoid membrane with int. laryngeal N. • Ascending pharyngeal artery. • Lingual artery : -arise opposite the greater horn of hyoid bone ,to enter submand.region and supply tongue. -it is crossed by hypoglossal N.

Branches of External Carotid Artery : • Facial artery : -it arises from ext.C.artery just above the greater cornu of hyoid bone.It has a wavycourse. -it ascends deep to and grooved post. part of submand.gland, then betweengland and body of mandible to pierce deep fascia at base of mandible to enter face. • Occipital artery : -It supplies back of scalp. • Posterior auricular artery : -arises at the level of upper border ofpost.belly of digastric to supply auricle. • Terminal branches :inside substance of parotid glandbehind neck ofmandible, it terminates into Superficial temporal + Maxillary arteries.

Internal Carotid Artery : • It arises at the upper border of thyroid cartilage (C4 vertebra). • It lies in the carotid sheath. • It enters the cranial cavity through the carotid canal. • It supplies the brain, eye, forehead, & nose • It has no branches in the neck. • Atherosclerosis in the neck…. visual defect due to insufficient blood flow through central artery of retina. • Insufficient blood flow in middle cerebral artey… motor & sensory loss.

Internal Carotid Artery : • Relations :Anterolaterally (superficial) : -Skin &fascia. -Ant.border of sternomastoid. -Post.belly of digastric. Above the digastric : -Stylohyoid, stylopharyngeus, styloglossus + glossopharyngeal N., pharyngeal branch of vagus, parotid gland, & external carotid artery (above). Posteriorly : sympathetic trunk,upper 3 cervical vertebrae. Medially : pharynx. Laterally : internal j.v. + vagusN.

Subclavian artery : • Origin :right from brachio-cephalicbehind sterno-clavicular joint., left from arch of aorta in sup.mediastinum. • Course :in the root of neck, it is divided into 3 parts by scalenusanterior. -1st part extends from its origin to medial border of scalenus ant. -2nd part lies posterior to this Ms. -3rd part extends from lat.border of scalenus ant. to outer border of 1st rib,where it becomes axillary Ar

1st part of Subclavian artery : • Relations :Anteriorly : -common carotid ,vagus, symp.trunk (ansa subclavia), int.j.v. & left phrenic N.Posteriorly :apex of lung &pleura, Rt.recurrent laryngealN • Branches : 1-vertebral artery.. 2-thyrocervical trunk. 3-internal thoracic(mammary) artery.

Scalenus Anterior & Phrenic nerve : • Note, the roots of phrenic N. lie laterally to scalenus anterior, but phrenic N. lies anterior to scalenus anterior.

1-Vertebral Artery : • Course : -it passes in front of T.process of 7th C.V. to ascend through foramina in transverse processesof upper 6 cervical vertebrae. -it emerges from T.process of atlas to pass behind its lateral mass,then pierces dura mater medially to enter vertebral canal and enter skull via foramen magnum to supply brain. Relations :-Anteriorly : C.C.artery and crossed by thoracic duct. Posteriorly :T.procees of 7thc.v. & stellate ganglion. Branches : spinal & muscular.

2-Thyro-cervical trunk : • It gives off 3 branches : 1-inferior thyroid artery : ascends along med.border of scalenus ant. to level of cricoid cartilage (C6V.) to reach post. border of thyroid gl.2-superficial cervical & 3- suprascapular arteries : they pass across scalenus anterior to enter post. triangle of the neck.

3-Internal thoracic artery : • Arises from lower border of 1stpart of subclavian artery. • Enters thorax behind 1st costalcartilage.

2nd part of subclavian : • Relations :Anteriorly : scalenus ant. Posteriorly : cervical pleura & apex of lung. • Branches : one branch….. Costo-cervical trunk : from its back. It gives off : 1-sup.intercostal artery : gives rise to 1st & 2nd post. Intercostal arteries. 2-deep cervical artery : to muscles of back of neck.

3rd part of subclavian : • Extends from lateral margin of scalenus ant. to the outer border of 1st rib ,where it becomes axillary artery. • It lies in post.triangle of neck.

Subclavian vein : • It begins at outer border of 1st rib as a continuation of axillary vein. • At medial border of scalenus ant., it joins int.j.v. to form brachiocephalic vein. • It lies in lower anterior corner ofpost.triangle of neck , posterior & close to undersurface of medial 1/3 of clavicle, so it is a safe site ofcatheterization ( infra-clavicular approach). • Its tributaries : Ext.J.V

Internal jugular vein : Course : • It receives blood from brain, face & neck . • It begins at jugular foramen as a continuation of sigmoid sinus. • It descends through the neck in the carotid sheath. • It unites with subclavian vein to form brachio-cephalic vein.

Tributaries of Internal jugular vein : • Inferior petrosal sinus :drains cavernus sinus, leaves skull via jugular foramen to join int.j.v.at its sup.bulb. • Pharyngeal veins. • Lingual vein. • Facial vein : leaves face superficially over submandibular gl. It joins ant.division of retromandibular v. to join the internal j.v. • Sup.thyroid vein : leaves sup.pole ofthyroid into int.j.v. • Middle thyroid vein : leaves lobe ofthyroid gl. to drain into int.J.V.

Venous drainage of thyroid gland

External jugular vein : • It lies in superficial fascia deep to platysma, lying on sterno-mastoid. • Just above the clavicle, it peirces deep fascia todrain into subclavianvein. • Structures superficial to sternocleidomastoid are : skin,platysma, external j.v.,great auricular N., transverse cervical N. & investing layer of deep cervicalfascia.

Internal j.v. catheterization : • Int.j.v. descends through neck from a point halfway between tip of mastoid process & angle of jaw to sternoclavicular joint. • In posterior approach,, the neddle & catheter are introduced into vein 2 fingers above clavicle at post. border of sternomastoid • In anterior approach,, the neddle & catheter are inserted into vein at the apex of triangle formed by sternal & clavicular heads of sternomastoid muscle.

Glossopharyngeal Nerve • Origin : Medulla Oblongata of Brain. • It has motor,sensory & parasymp.Fs. • Course & relations :-It has 2 sensory ganglia (sup.& inf.) in thejugular foramen-It leaves skull through jugular foramen to descend in the upper neck within carotid sheath. -It leaves carotid sheath to pass between internal & external C. Ar. -It winds around stylopharyngeus Ms. between Sup. & middleconstrictors of pharynx into the back of tongue deep tohyoglossus.-it terminates by dividing into terminalbranches supplying m.m.of pharynx, tonsils, soft palate & post.1/3 of tongue

Branches of Glossopharyngeal N. • Tympanic branch : arises from inf.ganglion, it hasparasymp. secreto-motor to parotid gland via auriculotemporal nerve. • Carotid branch : sensory to carotid sinus & carotid body . • Muscular :motor to Stylopharyngeus. • Pharyngeal branches (sensory) : toform the sensory part of pharyngealplexus tosupply m.m. ofpharynx, tonsils, & soft palate. • Lingual terminal branches : for general & taste sensation of post.1/3 of tongue.

Vagus Nerve • Origin : It emerges from M.O. to leave the skull with 9th & 11th Ns. through jugular F. • It has motor, sensory & parasympathetic Fs. • Course : • It has 2sensory ganglia , superiorwithin j.F. & inferior just below j.F. • At inf. ganglion, cranial root ofaccessory N. joins vagus N. and distributed in its pharyngeal &recurrent laryngeal branches.

Vagus nerve : • It descends in the upper part ofneckwithin carotid sheath, firstly between int.j.v.& int.c.Ar., then between Int. j.v. & C.C.Ar. • At the root of neck, it lies in front ofto 1st part of subclavian Ar. It passes through thorax and pierces diaphragm at esophageal opening to end in abdomen. • It innervates heart,/ respiratory passages, / G.I.T.( pharynx- left colic flexure), liver & pancreas.

Branches of Vagus nerve : From superior ganglion : 1-meningeal branch.2-auricular br. for ext. acoustic meatus. From inferior ganglion :3-Pharyngeal br. : to form Motor part ofpharyngealplexus, to supply all Ms.of pharynxexcept Stylopharyngeus (by glossopharyngeal N.), + all Ms.of soft palateexcept tensor velipalatini (by mandibular division of trigeminal).4-Superior laryngeal N. ,it divides into : a-Internal laryngeal N., pierces thyrohyoid membrane with sup. laryngeal artery, to supply sensory F. to m.m. of upper part of larynx above vocal fold.b-External laryngeal N., to supply Cricothyroid ms.

Branches of Vagus nerve : 5- cardiac branches :parasymp.,to end in cardiac plexus in the thorax. 6- Right recurrent laryngeal N. : it hooks behind 1st Subclavian artery to ascend in groove bet. trachea & esoph. to supply all Ms.of larynx (motor) except Cricothyroid , + m.m. of larynx (sensory), below vocal folds.7- left R.L.N. : it hooks around arch of aorta ,behind ligamentum arteriosum, then ascends into neck in groove bet. trachea & esoph….as Rt.R.L.N.

Testing the Integrity of Vagus nerve : • Depends on testing the function of branches to pharynx, soft palate,& larynx. • Pharyngeal reflex or gag-reflex may be tested by touching lateral wall of pharynx with spatula causing the patient to gag dueto contraction of pharyngeal Ms. • Innervation of soft palate can be tested by saying ‘ah’, normally soft palate rises anduvula moves backward in the middle. • Lesion of innervation of larynx may reveal in horseness or absence of voice, and laryngoscopic examination may reveal paralysis of abductor muscles of larynx.

Accessory nerve • It is purely motor N., formed by union of cranial & spinal roots. • Cranial root arises from M.O. • Spinal root arises from upper 5cervical segments of spinal cord, It enters skull through the foramen magnum to join the cranial root within the cranial cavity. • Both roots form the united trunk that emerges from jugular F. Distribution of Accessory N.

Branches of Accessory nerve : • Cranial root separates from spinal root to join vagus at its inferior ganglion to distribute through its pharyngeal & laryngeal branches to supply Ms. of soft palate & pharynx (via pharyngeal plexus) and to Ms. of larynx (via R.L.N, except cricothyroid). • Spinal root pierces deep surface of Sternomastoid to supply it , then emerges from posterior border of sternomastoid and crosses post. triangle, lying on the levator scapulae, finally passes deep to trapezius to supply it. Distribution of Accessory N.

Testing the Integrity of Accessory nerve : • Accessory N. supplies sternomastoid & trapezius Ms. by its spinal root. • Aske the patient to rotate head to one side against resistance causing contraction of sternomastoid of opposite side. • Aske the patient to shrug the shoulders causing action of trapezius, to compare the power on the 2 sides. Distribution of Accessory N.

Pharyngeal plexus of nerves • It lies on the outer wall of pharynx, mostly on the midlle constrictor. • It is formed ofpharyngeal branches of glossopharyngeal N. (sensory part) + of vagus N. including fibres of cranial root of accessory(motor part) + of superior cervical sympathetic ganglion (sympathetic part), to supply pharynx & soft palate.

Hypoglossal Nerve • Origin : Arises from M.O. to leave skull via hypoglossal canal . • It is purely motor N. to the tongue. • Course: In its upper part, it is joined by a branch from cervical plexus (C1N.) to supply thyrohyoid & geniohyoid. • later it leaves hypoglossal N. as descending branch of hypoglossal N. Distribution of Hypoglossal N.

Hypoglossal Nerve • It descends with the vagus N. between int.j.v. & int.C.artey, then crosses in frontofinternal & external carotid arteries. • Then it crosses in front oflingual artery to enter submandibular region.

Branches of Hypoglossal Nerve : • Meningeal branch. • N.to Thyrohyoid & Geniohyoid (via C1). • Descending branchof hypoglossal C1 leaves hypoglossal N. in front ofcarotid sheath to join the descendingcervical N.(C2,3) of cervical plexus to form a loop ofAnsacervicalis. • Ansa cervicalis loop supplies omohyoid, sternohyoid & sternothyroid Ms. • Muscular branches : to all Ms.of tongue, Except palatoglossus, (supplied by pharyngeal plexus) Distribution of Hypoglossal N.

Hypoglossal N. lesion • Ask the patient to protrude his tongue : • A, Rt.&Lt. genioglossus muscle contract together. • B, tip of tongue is protuded anteriorly in the middle line. • C, lesion of hypoglossal N. on Rt. Side leads to atrophy & wrinklingof the tongue on the same side of lesion. • D, when asking patient to protrude the tongue, the tip deviates to side of the lesion.

Cervical Plexus : Formation : • It is formed by union of anteriorrami of upper 4 cervicalnerves, which form loops that lie in front of levator scapulae & scalenus medius. • It lies behindprevertebral layer of deep cervical fascia , int. J.V.,carotid sheath & Sternomastoid.

Branches of Cervical Plexus : • Cutaneous : lesser occipital (C2), great auricular (C2,3), transverse cutaneous (C2,3)& supraclavicular nerves (C3,4), which enter post.triangle. • Muscular to 1-prevertebral Ms., 2-sternomastoid (proprioceptiveC2,3), 3-(C3,4) to supply : -diaphragm (phrenic N.) -Trapezius & levator scapulae. 4- C2,3 - inferior root of Ansa cervicalis it unites with superior root of Ansa cervicalis (C1) to formloop of Ansacervicalis to supply infrahyoid Ms. :omohyoid,sternohyoid & sternothyroid.

Branches of Cervical Plexus : • Communicating branches :- C1 fibres join hypoglossal N. - Grey rami communicantes : from superior cervicalsympathetic ganglion to C1,2,3,4 Formation & Branches of Ansa Cervicalis

Cervical part of Symp.Trunk : • It extends frombase of skull ,to the neck of 1st rib, where it becomes the thoracic part. • It lies in front ofcervical transverse processes,longus capitis & longus colli Ms., behindcarotid sheathmedial tovagus N.& vertebral artery. • It has 3 ganglia., superior, middle & inferior (cervico-thoracic or stellate ganglion).

Cervical part of Sympathetic Trunk • Anterior relations : carotid sheath. • Posterior relations : 1-Cervical transverse processes. 2-Longus capitis & longus colli (prevertebral muscles). • Lateral relations :1-vagus N.2-vertebral artery… (except inferior or stellateganglion,which lies behind vertebral artery).

Superior Cervical Symp. Ganglion • It is the largest ganglion, lies at the level of C2,3 vertebrae. • Branches :1-Internal carotid nerve : it accompanies the int.c.Ar. into carotid canal ,where it divides into branches to form internal carotid plexus.2-Gray rami communicates to the upper 4 anterior rami of cervical nerves 3-External carotid nerve : it divides into branches to form symp.plexus around ext.C.artery & its branches. 4-Cranial N.branches : which join 9th ,10th , & 12th cranial nerves.

Superior Cervical Symp. Ganglion 5-Pharyngeal branches :which unitewith the pharyngeal branches of glossopharyngeal(9) & vagus(10) nerves toform the pharyngeal plexus. 6-Superior cardiac branch :which endsin cardiac plexus in thorax.

Middle Cervical Symp.Ganglion : • It lies at level of cricoid cartilage (opposite 6th C.V.). • Branches :1-Gray rami communicates to anterior rami of 5th & 6th cervical nerves. 2-Thyroid branches : which pass along inferior thyroid artery to form plexus to supply thyroid gland.3-Middle cardiac branch : which ends in cardiac plexus in thorax. 4-Ansa suclavia : it forms a loop around 1st part of subclavian artery (in front, then behind artery) to join inferior cervical symp. ganglion.

Common Carotid Artery :