nerve suply to head and neck

8/17/2019 Nerve Suply to Head and Neck

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Nerve supply of Head & Neck

• Facial nerve CN VII

•

Vestibulo cocchlear nerve CN VIII

• Glossopharyngeal nerve CN IX

• Vagus nerve CN X

• Spinal accessory nerve CN XI

• Hypoglossal nerve CN XII

• Facial Nerve ⇒

⇒ CN VII

⇒ Mixed motor sensory

⇒ Supplies mainly to muscles o! !acial expression

Nuclei ⇒

Motor nucleus is in the pons

"art o! motor nucleus that supplies the muscles o! upper part

o! !ace receives corticonuclear #bers !rom both the sides o!

cerebral hemisphere$ %he part o! nucleus that supplies the

muscles o! lo&er part o! the !ace receives corticonuclear #bers

only !rom contralateral cerebral hemisphere$

Parasympathetic nuclei '

Superior Salivary Nucleus


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(acrimatory nucleus

Sensory nucleus

)pper part o! the nucleus o! the tractus selitanius

Course of the Facial nerve ⇒

- Motor * sensory root

- Sensory root is also called as nervous intermedius$ It is

!ormed by the central processes o! the unipolar cells o! the

geniculate ganglion$ It also contains parasympathetic

#bers$

- %&o roots o! CN VII emerges !rom the anterior sur!ace o! the

brain bet&een pons and medulla$

-+nters the internal acoustic meatus in petrous temporal

bone$

- +nters the !acial canal$

- ,uns laterally through the inner ear

- -n reaching the medial &all o! typanic cavity nerve

explands to !orm the geniculate ganglion$

- It emerges !rom the stylomastoid !aramen$

- Nerve lies about .cm deep to the middle o! the anterior

border o! the mastrid process$

Extracranial course ⇒


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It crosses the lateral side o! the base o! the styloid process$ It

enters the posteromedial sur!ace o! the porotid gland/ runs

!or&ards through the gland crossing the retromandibular vein

and the external carotid artery$ 0ivides into #ve terminal

branches$ It lies .cm deep to the ante border o! mastoid

process$

Branches ⇒

12 3ithin the !acial canal

42 Greater "etrosal nerve

.2 Nerves to the stapedius

52 Chorda tympani

62 1s it exits !rom the stylomastoid !oramen

42 "osterior auricular

.2 0igastric 7"osterior belly2

52 Stylohyoid

C2 %erminal branches

42 %emporal 8 1uricular muscles occipito !rontalis muscle

and other muscles

.2 9ygomatic 8 orbicularis oculi

52 6uccal 8 orbicularis oris/ levator labi superioris


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:2 Mandibular 8 (o&er lip * chin muscles/ levator angulions

;2 Cervical 8 "latysma * other muscles

02 Communicating branches &ith the ad


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Paralysis of facial nerve

Facial "alsy

-

)pper motor neuron

- (o&er motor neuron

+g$ ' 6ellAs "alsy

Upper motor neuron Paralysis

7Supranuclear "aralysis2

In this type/ only the lo&er part o! the !ace is a=ected on

contralateral side upper part o! !ace is spared because it has a

bilateral innervation o! corticonuclear and corticobulbar #bers$

e$g$ ' due to extradural haemorrhage$

Loer motor neuron Paralysis

- Complete "aralysis o! !ace on a=ected side$

- 6ellAs "alsy is a idiopathic/ unilateral lo&er motor neuron

"aralysis o! !acial nerve$

- Name &as given by Sir Charles 6ell in 4B.4$

- F M

- More in middle aged people$

- "ositive !amily history in BD people$

- 54D o! patient &ith 6ellAs "alsy recurrence are diabetics$


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!yndromes associated ith facial nerve "

42 MelEersson 8 ,osenthal Syndrome

7-ro!acial granulomatosis2

- Facial "aralysis

- Non tender persistant s&elling o! upper and lo&er lips

present

.2 Crocodile %ear Syndrome

- 0ue to in


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- 6ilateral !acial paralysis$

42 #erti$ulocochlear Nerve

- Bth CN

- Special sensory

- Special sense o! Hearing * euillibrium

Nuclei

- : vestibular nuclei

- In medulla * pons

- . cochlear nuclei

- In relation to in!erior cerebellar peduncle$

- CN VIII emerges !rom the


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Cochlear nerve

- Hearing

-

Spiral ganglion

- "eripheral processes o! bipolar neurons o! spiral ganglion

supplies organ o! corti/ situated in the cochlear duct o!

internal ear$

- "eripheral processes !orms the cochlear nerve$

%pplied aspects

- Vestibulocochlear nerve in


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'eniere !yndrome

- ,ecurrent attacEs o! tinnitus/ hearing loss/ vertigo$ It is due

to the increase in the volume o! endolymph in the

membranous labyrinth o! the internal ear$

(est for deafness

Vibrating tuning !orE is held opp$ to the external acousting

meatus and then held on the mastoid process$ I! dea!ness is

due to conduction !ailure/ sound is heard normally &hen the

tuning !orE is placed on mastoid process$ In case o!

sensorineural dea!ness hearing o! sound in both regions is

a=ected$ It is called as ,innAs test$

)* +lossopharyn,eal nerve

- gth CN

- Motor Sensory

- Nerve o! 5rd branchial greb

-Nuclei ⇒ 5 in no$

42 Main motor nucleus 8 lies deep in the medulla oblongata$

.2 In!erior Salivatory nucleus

"arasympathetic nucleus

52 Sensory nucleus

"art o! nucleus o! tractus solitarius$


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⇒ 1rises !rom the upper part o! medulla oblongata as a series

o! rootlets$

It passes laterally in the "osterior cranial !ossa and leaves the

sEull through the


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- 0escends on the internal carotid artery and supplies carotid

body * sinus$

52 "haryngeal branches

- Forms "hanyngeal plexus

- Supplied to the mucous membrane o! the pharynx$

:2 MusculaEr branch

%o stylopharyngeus

;2 %onsillar branches

- %onsil

- Loins the lesser petrosal nerve to !orm plexus !rom &ith

#bers are supplied to so!t palate and to the palatoglossal

arches$

2 (ingual branches

- %aste !rom "osterior .@5rd o! tongue

- General sensation

%pplied anatomy

- Isolated lesions o! the glossopharyngeal nerve are rare and

usually also involve the vagus nerve$


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- +lossopharyn,eal neural,ea

- Sharp shooting pain in the ear and the pharynx/

nasopharynx/ tonsil and the posterior part o! the tongue$

- )nilateral and paroxysmal

- %rigger ones in posterior part o! the tongue

- )nilateral and paroxysmal

- %rigger ones in posterior oropharynx and tonsillar !ossa$

-

Idopathic

- 6ecause CN IX/ X * XI pass through the


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52 Sensory nucleus 8 7Gustatory2 (o&er part o! nucleus o!

tractus solitarius$

:2 Spinal nucleus o! trigeminal nerve$

- Nerve is attached by means o! about ten rootlets to the

posterolateral sur!ace o! o! medulla$

- ,ootlets unites to !orm one trunE$

-

Nerve passes laterally in the posterior cranial !ossa and

leaves the sEull through the


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b2 1uricular branch 8

- Supplies Concha and root o! the auricle/ posterior hal! o!

external auditory meatus/ outer sur!ace o! typanic

membrane$

- communicating branches to CN IX * XI$

Branches in the neck

a* "haryngeal branch

- 1rises !rom in!erior ganglion o! vagus$

- Contains #bers o! cranial root o! accessory$

- "asses to upper border o! middle constrictor and !orms the

pharyngeal plexus and #nally supplied to muscles o!

pharynx and so!t palate$

$* Corotid branches 8 to carotid body and sinus

c* Superior laryngeal nerve 8

- 1rises !rom the in!erior ganglion$

-,uns do&n&ards and !or&ards$

- ,eaches the middle constrictor o! "harynx and gets divided

in to

i2 +xternal laryngeal nerve

- 1ccompanies sup$ thyroid artery

-Supplies cricothyroid muscle/ in!erior constrictor$


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ii2 Internal laryngeal nerve

- Supplies the mucous membrane o! the larynx up to the level

o! vocal !olds$

d* /i,ht recurrent laryn,eal nerve

- 1rises !rom ,t$ vagus in !ront o! right subclavian artery$

- ,uns up&ards and medially behind the subclavian and

common carotid arteries$

- It supplies all the intrinsic muscles o! larynx except the

cricothyroid$ It is sensory to the larynx belo& the level o!

vocal cords$

(e!t recurrent laryngeal nerve arises !rom the lt$ vagus in

thorax$

e* Cardiac $ranches

- Superior and in!erior branches helps in the !ormation o! the

cardiac plexus$

-Vagus nerve enters the thorax and helps in the !ormation o!

- Cardiac plexus

- "ulmonary plexus

- ,t$ Vagus is Eno&n as "osterior vagal trunE in the abdomen


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- (t$ vagus is Eno&n as 1nterior vagal trunE in the

abdomen$

- 0istributed to liver/ Eidneys/ deuodenum and small and

large intestines$

- (esion o! superior laryngeal nerve$

- Voice is &eaE and tires easily$

0n1ury to recurrent laryn,eal nerve

- hoarseness and dysphonia because o! paralysis o! vocal

!olds

"aralysis o! both nerves causes aphonia and inspiratory

stridor$

%here is cadaveric position o! the vocal cords 7i$e$ bet&een

adduction and abduction2$

--* %ccessory nerve

- 44th CN

-Motor

- %&o roots/ cranial and spinal

Nuclei

- cranial root arises !rom the lo&er part o! nucleus ambigus$


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- Spinal root arises !rom a long spinal nucleus situated on the

lateral part o! anterior gray column o! spinal cord/ extending

!rom C4 to C; segment$

- Cranial root

1ttached to the posterolateral sulcus o! medulla by :;

rootlets$

,ootlets


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- "ierces the anterior border o! SCM muscle at 4@:th * 5@:th

level$

- +nters the posterior triangle o! necE$

- Supplies the trapeius muscle

- Spinal root communicate &ith spinal nerves C5 and C:$

%pplied aspects

(esion o! the accessory nerveOsA spinal part &ill cause the

paralysis o! the trapeius and SCM$ ,esults in &eaEness in

turning the head to the opposite side$

1trophy o! the muscles$

Irritation o! spinal accessory nerve due to inammed or

suppurating cervical lymph nodes causes >reex torticollis?$

%here is spasm or contracture o! the muscles 7SCM and

trapeius2 &hich results in head being bent to the one side and

chin points to the other side$ %orticollis is also Eno&n as O3ry

necE?$

-2* Hypo,lossal nerve

- XII CN

- Motor


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- Supplies all the intrinsic muscles o! tongue and extrinsic

muscles o! tongue 7styloglossus/ hyoglassus and

genioglossus2 7except palatoglossus2

- Controls the shape and movements o! tongue$

Nucleus

- Motor nucleus situated close to the midline immediately

beneath the oor o! the lo&er part o! the !ourth ventricle$

Course

1rises !rom the medulla 7antenolateral sulcus2 by several

rootlets$

(eaves the sEull through the hypoglossal canal$ 1!ter emerging

!rom the canal nerve is


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- 1 descending branch


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'%'%(% EN(%L C4LLE+E

Department of

Oral & Maxillofacial Surgery

Nerve Supply of Head & Neck


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Moderator Presented by

r5 !udheer r5 !ati 65

Chidraar'! P5+5 ept5 of 4'F!

nerve suply to head and neck

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