No. 33No. 33

ⅦⅦ--Ⅻ pairs of Cranial Nerves--Ⅻ pairs of Cranial Nerves

Ⅶ Ⅶ Facial NerveFacial Nerve

Ⅰ Ⅰ) Fibrous components:) Fibrous components: It is a mixed nerve, it contains four components:It is a mixed nerve, it contains four components: (1) The special visceral motor fibers(1) The special visceral motor fibers They take origin from the facial nucleus and supply thThey take origin from the facial nucleus and supply th

e muscles of expression.e muscles of expression. (2) The general visceral motor fibers(2) The general visceral motor fibers They arise from the superior salivatory nucleus and arThey arise from the superior salivatory nucleus and ar

e relayed in certain parasympathetic ganglia. The poste relayed in certain parasympathetic ganglia. The postganglionic fibers are distributed to the lacrimal gland, ganglionic fibers are distributed to the lacrimal gland, the submandibular and sublingual salivary glands and the submandibular and sublingual salivary glands and glands in the mucous membrane of the nose and palaglands in the mucous membrane of the nose and palate.te.

(3) The special visceral sensory fibers(3) The special visceral sensory fibers They arise from the cells of the geniculate ganThey arise from the cells of the geniculate gan

glion. The central processes of these cells termglion. The central processes of these cells terminate in the nucleus of solitary tract. The peripinate in the nucleus of solitary tract. The periphery processes of these cells are distributed to hery processes of these cells are distributed to the taste buds on the anterior 2/3 of the tonguthe taste buds on the anterior 2/3 of the tongue.e.

(4) The general somatic sensory fibers(4) The general somatic sensory fibers They connect the somatic sensation of skin in They connect the somatic sensation of skin in

ear and the proprioceptive sensation of the mear and the proprioceptive sensation of the muscles of expression.uscles of expression.

Ⅱ Ⅱ) Course:) Course: The facial nerve leaves the brain at the bulbopontine sThe facial nerve leaves the brain at the bulbopontine s

ulcus just medial to the vestibulocohlear nerve. It passulcus just medial to the vestibulocohlear nerve. It passes laterally and forwards with that nerve to the internes laterally and forwards with that nerve to the internal acoustic pore. At the bottom of the meatus, the facial acoustic pore. At the bottom of the meatus, the facial nerve enters the facial canal, where it turns sharply al nerve enters the facial canal, where it turns sharply downward and backward behind the middle ear. The downward and backward behind the middle ear. The geniculate ganglion is located at the entrance of facial geniculate ganglion is located at the entrance of facial canal as an enlargement of the nerve. The nerve emercanal as an enlargement of the nerve. The nerve emerges onto the side of the face through the stylomastoid ges onto the side of the face through the stylomastoid foramen, then runs forward into the parotid gland.foramen, then runs forward into the parotid gland.

Ⅲ Ⅲ) Branches and distribution) Branches and distribution 1. The branches within the facial canal1. The branches within the facial canal 1) The 1) The greater petrosal nervegreater petrosal nerve It includes secretary fibers of parasympathetic It includes secretary fibers of parasympathetic

nerve. It arises from the geniculate ganglion anerve. It arises from the geniculate ganglion and runs forward and passes through the base nd runs forward and passes through the base of skull to the pterygopalatine fossa and enterof skull to the pterygopalatine fossa and enters the pterygopalatine ganglion; the postganglis the pterygopalatine ganglion; the postganglionic fibers are distributed to the lacrimal glanonic fibers are distributed to the lacrimal gland and the glands of the nose and palate.d and the glands of the nose and palate.

2) The 2) The chorda tympanichorda tympani It arises from the facial nerve about 6 mm aboIt arises from the facial nerve about 6 mm abo

ve the stylomastoid foramen.ve the stylomastoid foramen. It travels upwards into the tympanic cavity goiIt travels upwards into the tympanic cavity goi

ng between the manubrium of malleus and tyng between the manubrium of malleus and tympanic membrane, and pierces the petrotymmpanic membrane, and pierces the petrotympanic fissure to leave the tympanic cavity to thpanic fissure to leave the tympanic cavity to the infratemporal fossa. Then, it runs downwarde infratemporal fossa. Then, it runs downwards and forwards to join the lingual nerve. The chs and forwards to join the lingual nerve. The chorda tympani contains two kinds of fibers:orda tympani contains two kinds of fibers:

① ① Its taste fibers (special visceral sensory fiberIts taste fibers (special visceral sensory fibers) are the peripheral processes of the cells of ts) are the peripheral processes of the cells of the geniculate ganglion and are distributed to the geniculate ganglion and are distributed to the mucous membrane covering the anterior 2/he mucous membrane covering the anterior 2/3 of the tongue, excluding the vallate papillae.3 of the tongue, excluding the vallate papillae.

② ② Its efferent preganglionic parasympathetic fiIts efferent preganglionic parasympathetic fibers enter the submandibular ganglion, which bers enter the submandibular ganglion, which sends postganglionic fibers to the submandibsends postganglionic fibers to the submandibular and sublingual glands.ular and sublingual glands.

3) Stapedial nerve3) Stapedial nerve It supplies the stapedius in the tympanic cavity.It supplies the stapedius in the tympanic cavity. 2. The branches outside the facial canal2. The branches outside the facial canal After the facial nerve exits from the stylomastoid foraAfter the facial nerve exits from the stylomastoid fora

men, it gives off three small branches supplying the ocmen, it gives off three small branches supplying the occipital belly of the occipitofrontalis, the posterior auricipital belly of the occipitofrontalis, the posterior auricularis, posterior belly of the digastric and the stylohycularis, posterior belly of the digastric and the stylohyoid.oid.

The principle stem of the facial nerve then runs forwarThe principle stem of the facial nerve then runs forward into the parotid gland and forms a network (parotid d into the parotid gland and forms a network (parotid plexus). At the anterior border of the parotid gland it dplexus). At the anterior border of the parotid gland it divides into 5 branches, and fans out to supply the musivides into 5 branches, and fans out to supply the muscles of expression:cles of expression:

① ① The The temporal branchestemporal branches It supplies the frontal belly of the occipitofrontalis, anIt supplies the frontal belly of the occipitofrontalis, an

d orbicularis oculi.d orbicularis oculi. ② ② The The zygomatic brancheszygomatic branches It supplies the orbicularis oculi and the zygomaticus.It supplies the orbicularis oculi and the zygomaticus. ③ ③ The The buccal branchesbuccal branches It supplies the buccinator, orbicularis oris and other mIt supplies the buccinator, orbicularis oris and other m

uscles around the mouth.uscles around the mouth. ④ ④ The The marginal mandibular branchmarginal mandibular branch It supplies the mucles of the lower lip.It supplies the mucles of the lower lip. ⑤ ⑤ The The cervical branchcervical branch It supplies the platysma.It supplies the platysma.

Ⅳ Ⅳ) The parasympathetic ganglia related to the facial n) The parasympathetic ganglia related to the facial nerveerve

1. The 1. The pterygopalatine ganglionpterygopalatine ganglion It lies in the pterygopalatine fossa under the maxillary It lies in the pterygopalatine fossa under the maxillary

nerve.nerve. The preganglionic parasympathetic fibers of the greatThe preganglionic parasympathetic fibers of the great

er petrosal nerve enter this ganglion.er petrosal nerve enter this ganglion. The postganglionic fibers pass along the zygomatic brThe postganglionic fibers pass along the zygomatic br

anch to the ophthalmic nerve to control the secretion anch to the ophthalmic nerve to control the secretion of the lacrinal gland.of the lacrinal gland.

The postganglionic fibers also manipulate the secretioThe postganglionic fibers also manipulate the secretion of the glands in the mucous membrane of the nasal n of the glands in the mucous membrane of the nasal cavity and palate.cavity and palate.

2. The 2. The submandibular ganglionsubmandibular ganglion It lies below the lingual nerve, deep to the subIt lies below the lingual nerve, deep to the sub

mandibular gland.mandibular gland. The preganglionic parasympathetic fibers of tThe preganglionic parasympathetic fibers of t

he chorda tympani enter this ganglion.he chorda tympani enter this ganglion. The postganglionic parasympathetic fibers are The postganglionic parasympathetic fibers are

distributed to the submandibular and sublingdistributed to the submandibular and sublingual glands and control their secretions.ual glands and control their secretions.

Ⅴ Ⅴ) The symptoms after injury of the facial nerv) The symptoms after injury of the facial nervee

1. The injury outside the facial nerve canal 1. The injury outside the facial nerve canal The main symptom is paralysis of muscles of eThe main symptom is paralysis of muscles of e

xpression.xpression. The face looks asymmetrical. The affected side The face looks asymmetrical. The affected side

of the face shows that the wrinkles on the foreof the face shows that the wrinkles on the forehead are smoothed out, the eye can not shut vhead are smoothed out, the eye can not shut voluntarily, the nasolabial fold becomes smootoluntarily, the nasolabial fold becomes smooth; the affected angle of mouth droop. h; the affected angle of mouth droop.

2. The injury inside the facial nerve canal2. The injury inside the facial nerve canal There is paralysis of the muscles of expression There is paralysis of the muscles of expression

as wella as the following symptoms:as wella as the following symptoms: The taste in the anterior 2/3 of the tongue is loThe taste in the anterior 2/3 of the tongue is lo

st. The secretion of the lacrimal, submandibulst. The secretion of the lacrimal, submandibular, and sublingual glands are decreased or lost.ar, and sublingual glands are decreased or lost.

ⅧⅧ. The Vestibulocochlear Nerve (C. The Vestibulocochlear Nerve (CN )ⅧN )Ⅷ

It is special somatic sensory nerve, consisting of It is special somatic sensory nerve, consisting of cochlcochlear nerveear nerve and and vestibular nervevestibular nerve..

Ⅰ Ⅰ) The vestibular nerve) The vestibular nerve It connects the sensation of equilibrium.It connects the sensation of equilibrium. The vestibular nerve arises from the bipolar nerve cellThe vestibular nerve arises from the bipolar nerve cell

s of the s of the vestibular ganglionvestibular ganglion situated in the bottom of situated in the bottom of the internal acoustic meatus. Its peripheral fibers terthe internal acoustic meatus. Its peripheral fibers terminate in the crista ampullaris and the macula of utricminate in the crista ampullaris and the macula of utriculi and sacculi; the central fibers pass into the brain at uli and sacculi; the central fibers pass into the brain at the pontocerebellar angle with the cochlear nerve.the pontocerebellar angle with the cochlear nerve.

Ⅱ Ⅱ) The cochlear nerve) The cochlear nerve It connects the acoustic sensation.It connects the acoustic sensation. The sensory fibers of the cochlear nerve take oThe sensory fibers of the cochlear nerve take o

rigin from the cells of the rigin from the cells of the cochlear ganglioncochlear ganglion si situated in the modiolus. The ganglion consists tuated in the modiolus. The ganglion consists of bipolar nerve cells, whose peripheral fibers of bipolar nerve cells, whose peripheral fibers distribute the spiral organs, while the central pdistribute the spiral organs, while the central processes pass into the brain through the internrocesses pass into the brain through the internal acoustic meatus, terminating the ventral anal acoustic meatus, terminating the ventral and dorsal nuclei of cochlear nerve.d dorsal nuclei of cochlear nerve.

Clinical significanceClinical significance:: The vestibulocochlear nerve is frequently injurThe vestibulocochlear nerve is frequently injur

ed together with the facial nerve in the fractured together with the facial nerve in the fracture of the base of skull which involves the interne of the base of skull which involves the internal acoustic meatus, or in the case of an acoustial acoustic meatus, or in the case of an acoustic tumor. Injuries of the internal ear may also cc tumor. Injuries of the internal ear may also cause the deafness and loss of the equilibrium.ause the deafness and loss of the equilibrium.

ⅨⅨ. The Glossopharyngeal Nerve . The Glossopharyngeal Nerve (CN )Ⅸ(CN )Ⅸ

Ⅰ Ⅰ) Fibrous components) Fibrous components It is a mixed nerve and contains five components.It is a mixed nerve and contains five components. ① ① The special visceral motor fibersThe special visceral motor fibers These fibers arise from the nucleus ambiguus to contrThese fibers arise from the nucleus ambiguus to contr

ol the stylopharyngeus.ol the stylopharyngeus. ② ② The parasympathetic nerve fibers (general visceral The parasympathetic nerve fibers (general visceral

motor fibers)motor fibers) They arise from the inferior salivatory nucleus and are They arise from the inferior salivatory nucleus and are

relay in otic ganglion. The postganglionic fibers are direlay in otic ganglion. The postganglionic fibers are distributed to the parotid gland and manipulate the secstributed to the parotid gland and manipulate the secretion of it.retion of it.

③ ③ The general visceral sensory fibersThe general visceral sensory fibers Its visceral sensory fibers are the peripheral prIts visceral sensory fibers are the peripheral pr

ocesses of the ocesses of the inferior ganglioninferior ganglion, to distribute , to distribute the mucous membrane of the pharynx, posterithe mucous membrane of the pharynx, posterior 1/3 of the tongue, tympanic cavity, auditory or 1/3 of the tongue, tympanic cavity, auditory tube, and the chemoreceptors in the carotid gltube, and the chemoreceptors in the carotid glomus and pressure receptors of the carotid sinomus and pressure receptors of the carotid sinus. The central processes terminate in the nuclus. The central processes terminate in the nucleus of solitary tract.eus of solitary tract.

④ ④ The special visceral sensory fibersThe special visceral sensory fibers The cell bodies of their neurons are in the The cell bodies of their neurons are in the

inferior ganglioninferior ganglion. The peripheral . The peripheral processes are distributed to the taste buds processes are distributed to the taste buds posterior 1/3 of the tongue, the central posterior 1/3 of the tongue, the central processes terminate in the nucleus of processes terminate in the nucleus of solitary tract.solitary tract.

⑤ ⑤ The general somatic sensory fibersThe general somatic sensory fibers These fibers are the peripheral processes These fibers are the peripheral processes

of the of the superior ganglionsuperior ganglion and supply the and supply the skin of the posterior surface of the auricle. skin of the posterior surface of the auricle. The central processes of the superior The central processes of the superior ganglion terminate in the spinal nucleus of ganglion terminate in the spinal nucleus of trigeminal nerve.trigeminal nerve.

Ⅱ Ⅱ) Route of glosopharyngeal nerve) Route of glosopharyngeal nerve It leaves (enters) the skull through the juIt leaves (enters) the skull through the ju

gular foramen.gular foramen. It passes forwards between the internal jIt passes forwards between the internal j

ugular vein and internal carotid artery to ugular vein and internal carotid artery to reach the styloid process, to the pharynx reach the styloid process, to the pharynx and breaks up into its terminal branches.and breaks up into its terminal branches.

Ⅲ Ⅲ) Branches of glosopharyngeal nerve) Branches of glosopharyngeal nerve ① ① The The lingual brancheslingual branches They are the terminal branches of glosopharyngeal neThey are the terminal branches of glosopharyngeal ne

rve, supplying the mucous membrane and taste buds rve, supplying the mucous membrane and taste buds of the posterior 1/3 of the tongue.of the posterior 1/3 of the tongue.

They connect general and special (taste) sensations.They connect general and special (taste) sensations. ② ② The The pharyngeal branchespharyngeal branches They supply the mucous membrane of the pharynx wiThey supply the mucous membrane of the pharynx wi

th sensory branches, the stylopharyngeus with motor th sensory branches, the stylopharyngeus with motor branch.branch.

③ ③ The The tympanic nervetympanic nerve It arises from the inferior ganglion of the glosopharynIt arises from the inferior ganglion of the glosopharyn

geal nerve and ascends to the tympanic cavity to form geal nerve and ascends to the tympanic cavity to form the the tympanic plexustympanic plexus..

Some small branches are distributed in the mucous mSome small branches are distributed in the mucous membrane of tympanic cavity, mastoid cells, and auditoembrane of tympanic cavity, mastoid cells, and auditory tube.ry tube.

The The lesser petrosal nervelesser petrosal nerve arises from this plexus and arises from this plexus and contains the preganglionic parasympathetic fibers frocontains the preganglionic parasympathetic fibers from the inferior salivatory nucleus), passes outside the tm the inferior salivatory nucleus), passes outside the tympanic cavity and joins the otic ganglion. The postgaympanic cavity and joins the otic ganglion. The postganglionic fibers pass through a communicating branch nglionic fibers pass through a communicating branch to the auriculotemporal nerve which carry the secretoto the auriculotemporal nerve which carry the secretomotor fibers to the parotid gland.motor fibers to the parotid gland.

The The otic ganglionotic ganglion is situated immediately bel is situated immediately below the foramen ovale, its pregnaglionic fibers ow the foramen ovale, its pregnaglionic fibers come from the lesser petrosal nerve. The postcome from the lesser petrosal nerve. The postganglionic fibers pass through a communicatiganglionic fibers pass through a communicating branch to the auriculotemporal nerve whicng branch to the auriculotemporal nerve which supplly the parotid gland. h supplly the parotid gland.

④ ④ The The carotid sinus branchcarotid sinus branch It is distributed to the wall of carotid sinus and It is distributed to the wall of carotid sinus and

the carotid glomus.the carotid glomus.

ⅩⅩ. The Vagus Nerve (CN )Ⅹ. The Vagus Nerve (CN )Ⅹ It is a mixed nerve. Its course is the longest and its distIt is a mixed nerve. Its course is the longest and its dist

ribution is the most extensive in the cranial nerves.ribution is the most extensive in the cranial nerves. Ⅰ Ⅰ) Components) Components It contains four components:It contains four components: ① ① The general visceral motor (parasympathetic) fibersThe general visceral motor (parasympathetic) fibers They arise from the dorsal nucleus of vagus nerve, and They arise from the dorsal nucleus of vagus nerve, and

end in the paraorganic or interorganic parasympathetend in the paraorganic or interorganic parasympathetic ganglions in the thoracic and abdominal cavities. Tic ganglions in the thoracic and abdominal cavities. The postganglionic fibers supply the smooth muscles, che postganglionic fibers supply the smooth muscles, cardiac muscles and glands of the viscera.ardiac muscles and glands of the viscera.

② ② The special visceral motor fibers.The special visceral motor fibers. They arise from the nucleus ambiguus and supThey arise from the nucleus ambiguus and sup

ply the striped muscles of the larynx and the pply the striped muscles of the larynx and the pharynx.harynx.

③ ③ The general visceral sensory fibersThe general visceral sensory fibers The cell bodies are located in the inferior gangThe cell bodies are located in the inferior gang

lion of vagus nerve. The central processes terlion of vagus nerve. The central processes terminate in the nucleus of the solitary tract. The minate in the nucleus of the solitary tract. The peripheral processes of this ganglionic cells arperipheral processes of this ganglionic cells are distributed to the viscera of the neck, thorax e distributed to the viscera of the neck, thorax and abdomen.and abdomen.

④ ④ The general somatic sensory fibers.The general somatic sensory fibers. The cell bodies of neurons are in the superior gThe cell bodies of neurons are in the superior g

anglion of vagus nerve. Their central processeanglion of vagus nerve. Their central processes enter the brain to terminate in the spinal nucs enter the brain to terminate in the spinal nucleus of trigeminal nerve. The peripheral procesleus of trigeminal nerve. The peripheral processes of this ganglionic cells supplies the skin of ses of this ganglionic cells supplies the skin of the auricle and external acoustic meatus and cthe auricle and external acoustic meatus and cerebral dura mater.erebral dura mater.

Ⅱ Ⅱ) Course) Course The vagus nerve is attached to the groove postThe vagus nerve is attached to the groove post

erior olive, and leaves the skull through the jugerior olive, and leaves the skull through the jugular foramen.ular foramen.

It then passes vertically down the neck within It then passes vertically down the neck within the carotid sheath behind the internal jugular the carotid sheath behind the internal jugular vein and the internal carotid artery (or the covein and the internal carotid artery (or the common carotid artery). mmon carotid artery).

Both vagus nerves descend through the inlet iBoth vagus nerves descend through the inlet into the thorax, situating behind the roots of lunto the thorax, situating behind the roots of lungs.ngs.

The left vagus nerve divides into several small branchThe left vagus nerve divides into several small branches to form the anterior esophageal plexus in front of tes to form the anterior esophageal plexus in front of the esophagus and forms the he esophagus and forms the anterioranterior vagal trunkvagal trunk at t at the lower end of the esophagus.he lower end of the esophagus.

The right vagus nerve forms the The right vagus nerve forms the posterior vagal trunposterior vagal trunkk on the back of the esophagus. on the back of the esophagus.

The anterior and posterior vagal trunks enter the abdThe anterior and posterior vagal trunks enter the abdominal cavity through the esophageal hiatus of the diominal cavity through the esophageal hiatus of the diaphragm and divide into their terminal branches near aphragm and divide into their terminal branches near the cardia of the stomach.the cardia of the stomach.

The anterior vagal trunk divides into the The anterior vagal trunk divides into the anterior gastanterior gastric branchesric branches and the and the hepatic brancheshepatic branches; the posterior ; the posterior vagal trunk divides into the vagal trunk divides into the posterior gastric branchposterior gastric brancheses and the and the celiac branchesceliac branches..

ⅢⅢ) Branches) Branches 1. The branches in the neck1. The branches in the neck 1) The 1) The superior laryngeal nervesuperior laryngeal nerve It arises from the inferior ganglion of the vagus nerve, It arises from the inferior ganglion of the vagus nerve,

descends by the side of the pharynx and medially to tdescends by the side of the pharynx and medially to the internal carotid artery.he internal carotid artery.

It divides into the internal and external branches at thIt divides into the internal and external branches at the greater horn of hyoid bone.e greater horn of hyoid bone.

The The internal branchinternal branch pierces the thyrohyoid membran pierces the thyrohyoid membrane and supplies sensory fibers to the mucous membrane and supplies sensory fibers to the mucous membrane of the larynx down as far as the level of the vocal fole of the larynx down as far as the level of the vocal folds.ds.

The The external branchexternal branch supplies the cricothyroid only. supplies the cricothyroid only.

2) The 2) The cervical cardiac branchescervical cardiac branches They join the cardiac branches of the sympathetic truThey join the cardiac branches of the sympathetic tru

nk, and form the superficial and deep cardiac plexusenk, and form the superficial and deep cardiac plexuses.s.

3) The 3) The pharyngeal branchpharyngeal branch They form the pharyngeal plexus to the muscles of the They form the pharyngeal plexus to the muscles of the

pharynx and the soft palate and the mucous membrapharynx and the soft palate and the mucous membrane of the pharynx.ne of the pharynx.

4) The ear branch4) The ear branch It contains the general somatic sensory fibers, supplyiIt contains the general somatic sensory fibers, supplyi

ng the skin of the auricle and external acoustic meatung the skin of the auricle and external acoustic meatus.s.

5) The meningeal branch5) The meningeal branch It is distributed in the cerebral dura mater.It is distributed in the cerebral dura mater.

2. The branches in the thorax2. The branches in the thorax 1) The 1) The recurrent laryngeal nerverecurrent laryngeal nerve The The right oneright one winds from before backwards round the winds from before backwards round the

subclavian artery, and ascends obliquely to the side of subclavian artery, and ascends obliquely to the side of the trachea behind the common carotid artery.the trachea behind the common carotid artery.

The The left oneleft one winds below the aortic arch immediately winds below the aortic arch immediately behind the arterial ligament to the concavity of the arbehind the arterial ligament to the concavity of the arch, and then ascends to the side of the trachea.ch, and then ascends to the side of the trachea.

The nerve on each side ascends in the groove betweeThe nerve on each side ascends in the groove between the trachea and esophagus, and enters the larynx ben the trachea and esophagus, and enters the larynx behind the cricothyroid joint, where they are named the hind the cricothyroid joint, where they are named the inferior laryngeal nerveinferior laryngeal nerve..

They give off branches to all the muscles of larynx, excThey give off branches to all the muscles of larynx, excepting the cricothyroid, and supply sensory fibers to tepting the cricothyroid, and supply sensory fibers to the mucous membrane of the larynx below the level of he mucous membrane of the larynx below the level of the vocal folds.the vocal folds.

Unilateral injury of the recurrent laryngeal nerve prodUnilateral injury of the recurrent laryngeal nerve produces the paralysis of vocal fold on the same side, resuluces the paralysis of vocal fold on the same side, resulting in a weak hoarse voice.ting in a weak hoarse voice.

Bilateral involvement of the recurrent laryngeal nerveBilateral involvement of the recurrent laryngeal nerves produces variable signs and symptoms. Hoarseness s produces variable signs and symptoms. Hoarseness even aphonia is present. Paralysis of the muscles in theven aphonia is present. Paralysis of the muscles in the aryepiglottic fold may result in the dysphagia (diffice aryepiglottic fold may result in the dysphagia (difficult to swallow) and regurgitation.ult to swallow) and regurgitation.

2) The 2) The broncheal branchesbroncheal branches and the and the esophageesophageal branchesal branches

They form the pulmonary plexus and esophagThey form the pulmonary plexus and esophageal plexus, supply their smooth muscles and gleal plexus, supply their smooth muscles and glands.ands.

3. The branches in the abdomen3. The branches in the abdomen 1) The 1) The anterior gastric branchesanterior gastric branches and and posterior gastriposterior gastri

c branchesc branches They are distributed to the stomach, the anterosuperiThey are distributed to the stomach, the anterosuperi

or surface of the stomach is mainly supplied by the anor surface of the stomach is mainly supplied by the anterior branches of the left vagal trunk and the posteroiterior branches of the left vagal trunk and the posteroinferior surface mainly by the posterior gastric branchnferior surface mainly by the posterior gastric branches of the right one.es of the right one.

The branches to the body and fundus of the stomach rThe branches to the body and fundus of the stomach regulate its gastric acid secretion.egulate its gastric acid secretion.

The branch to the pyloric part of the stomach regulateThe branch to the pyloric part of the stomach regulates the hormone gastrin and in relation to emptying the s the hormone gastrin and in relation to emptying the stomach. The branch reaching to the pyloric canal anstomach. The branch reaching to the pyloric canal and pylorus is named the “d pylorus is named the “crow’s footcrow’s foot”.”.

2) The hepatic branches2) The hepatic branches They join the They join the hepatic plexushepatic plexus and then supply and then supply

the liver and gallbladder to regulate the bile sethe liver and gallbladder to regulate the bile secretion.cretion.

3) The celiac branches3) The celiac branches They join the celiac plexus and accompany witThey join the celiac plexus and accompany wit

h the celiac artery, superior mesenteric and reh the celiac artery, superior mesenteric and renal arteries to supply the liver, spleen, pancreanal arteries to supply the liver, spleen, pancreas, small intestine, cecum and appendix, ascens, small intestine, cecum and appendix, ascending colon, right half of transverse colon, kidnding colon, right half of transverse colon, kidneys and suprarenal glands.eys and suprarenal glands.

Ⅳ Ⅳ) Clinical points) Clinical points The secretion of the gastric acid is regulated by the vaThe secretion of the gastric acid is regulated by the va

gus nerve. The section of vagus nerve can reduce the gus nerve. The section of vagus nerve can reduce the production of acid in the person with peptic ulcer. Oftproduction of acid in the person with peptic ulcer. Often a highly selective vagotomy is done during which oen a highly selective vagotomy is done during which only the twigs to the wall of stomach before the “cronly the twigs to the wall of stomach before the “crow’s foot” are sectioned. This operation has twofold w’s foot” are sectioned. This operation has twofold effects of reducing the acid secretion and keeping the effects of reducing the acid secretion and keeping the function of the pylorus and other abdominal organs wfunction of the pylorus and other abdominal organs which are supplied by the vagus nerve.hich are supplied by the vagus nerve.

ⅪⅪ. The Accessory Nerve (CN )Ⅺ. The Accessory Nerve (CN )Ⅺ

It is a motor nerve, formed by the union of the cranial It is a motor nerve, formed by the union of the cranial and spinal roots.and spinal roots.

The smaller The smaller cranial rootcranial root arises from the lower part of t arises from the lower part of the nucleus ambiguus and emerges from the side of thhe nucleus ambiguus and emerges from the side of the medulla below the rootlets of the vagus nerve by 4—e medulla below the rootlets of the vagus nerve by 4—5 rootlets. The cranial root passes through the jugular 5 rootlets. The cranial root passes through the jugular foramen and joins the vagus nerve immediately to forforamen and joins the vagus nerve immediately to form the component of pharyngeal branch and recurrent m the component of pharyngeal branch and recurrent laryngeal nerve of the vagus nerve to the muscles of tlaryngeal nerve of the vagus nerve to the muscles of the soft palate and intrinsic muscles of the larynx.he soft palate and intrinsic muscles of the larynx.

The larger The larger spinal rootspinal root arises from the accessory arises from the accessory nucleus in the anterior horn of the upper 5—6 nucleus in the anterior horn of the upper 5—6 cervical segments. It emerges from the spinal cervical segments. It emerges from the spinal cord by rootlets between the anterior and cord by rootlets between the anterior and posterior rootlets of the spinal nerves.posterior rootlets of the spinal nerves.

The spinal root ascends and enters the skull The spinal root ascends and enters the skull through the foramen magnum. It then passes through the foramen magnum. It then passes upward and laterally to the jugular foramen, upward and laterally to the jugular foramen, where it unites the cranial root to form the where it unites the cranial root to form the accessory nerve and passes through this foramen accessory nerve and passes through this foramen for a short distance.for a short distance.

It leaves the cranial root, passes backward and It leaves the cranial root, passes backward and downward to the sternocleidomastoid, which idownward to the sternocleidomastoid, which it pierces and supplies, and then crosses the pot pierces and supplies, and then crosses the posterior triangle of the neck to enter and supply sterior triangle of the neck to enter and supply the deep surface of the trapezius.the deep surface of the trapezius.

In fracture or other damage involving the jugulIn fracture or other damage involving the jugular foramen, the glossopharyngeal, vagus and aar foramen, the glossopharyngeal, vagus and accessory nerves may be damaged together. Thccessory nerves may be damaged together. The symptoms and signs of this condition are cale symptoms and signs of this condition are called the jugular foramen syndrome.led the jugular foramen syndrome.

Unilateral lesion of accessory nerve usually doUnilateral lesion of accessory nerve usually does not produce an abnormality in the position es not produce an abnormality in the position of the head. However, weakness in turning the of the head. However, weakness in turning the head to the opposite side against resistance chead to the opposite side against resistance can be detected due to the sternocleidomastoian be detected due to the sternocleidomastoid muscle paralysis.d muscle paralysis.

Unilateral paralysis of the trapezius may prodUnilateral paralysis of the trapezius may produce dropping of the shoulder.uce dropping of the shoulder.

ⅫⅫ. The Hypoglossal Nerve (CN )Ⅻ. The Hypoglossal Nerve (CN )Ⅻ

It is the motor cranial nerve and arises from the hypogIt is the motor cranial nerve and arises from the hypoglossal nucleus.lossal nucleus.

Its 10—15 rootlets emerge from the medulla oblongatIts 10—15 rootlets emerge from the medulla oblongata between the olive and the pyramid. The rootlets unita between the olive and the pyramid. The rootlets unite to leave the skull by way of the hypoglossal canal.e to leave the skull by way of the hypoglossal canal.

The nerve descends between the internal carotid arterThe nerve descends between the internal carotid artery and the internal jugular vein. At the level of the angle y and the internal jugular vein. At the level of the angle of mandible it passes forward over the internal and exof mandible it passes forward over the internal and external carotid arteries and gives off its descending and ternal carotid arteries and gives off its descending and thyrohyoid branches. It then goes forwards over the hthyrohyoid branches. It then goes forwards over the hyoglossus to enter the tongue.yoglossus to enter the tongue.

The hypoglossal nerve supplies all the extrinsiThe hypoglossal nerve supplies all the extrinsic and intrinsic muscles of the tongue (with the c and intrinsic muscles of the tongue (with the exception of the palatoglossus).exception of the palatoglossus).

Injury to the hypoglossal nerve results in paralInjury to the hypoglossal nerve results in paralysis and atrophy of the affected side of the tonysis and atrophy of the affected side of the tongue. The tongue deviates to the paralyzed side gue. The tongue deviates to the paralyzed side during protrusion because of the action of the during protrusion because of the action of the unaffected genioglossus muscle on the other sunaffected genioglossus muscle on the other side.ide.