8/3/2019 Last 4 Cranial Nerves

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Created by Qosru Iskandariah

LAST 4 CRANIAL NERVES

Nerve Glossopharyngeal (9th) Vagal (10

th) Accessory (11

th) Hypoglossal (12)

Origin Medulla oblongata 2 parts:

-Cranial part: Medulla oblongata-Spinal part: Upper 5 cervical

segments

Medulla oblongata

Course Passing throughjugular foramen

deep to styloid process and

apparatus to leave the skull

Lies between internal and

external carotid arteries

Runs on stylopharyngeus

Passes between superior and

middle constrictor of pharynx

Lies on medial surface of

hyoglossus muscle

Ends in posterior 3rd oftongue

Passing throughjugular foramen to

leave posterior cranial fossa

Descends within carotid sheath

between internal jugular vein and

internal carotid artery

At level of upper border of thyroidcartilage, it lies between internal

jugular vein and common carotid

artery

Enters thorax by crossing 1st

part of

subclavian artery

CRANIAL PART:

Passing throughjugular foramen

to join with spinal part

Separates from spinal part below

the skull

Joins with vagus and is distributed

through pharyngeal and laryngeal

branches

SPINAL PART:

Passing through foramen magnum

Joins with cranial part at jugular

foramen

Separates from cranial partbelow the skull

Descends deep to styloid process

Pierces sternomastoid muscle

Passing through hypoglossal canal to

leave the skull

Lies deep to carotid sheath and

structures passing through it

(glossopharyngeal, vagal and

accessory nerves)

Passes deep to posterior belly of

digastric and stylohyoid muscles

Crosses internal and external

carotid arteries, loop of lingual

artery

Passes lateral to hyoglossus muscle

along upper border ofhyoid bone

deep to submandibular gland

Terminate at muscles of tongue

8/3/2019 Last 4 Cranial Nerves

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Created by Qosru Iskandariah

Crosses posterior triangle

Pierces trapezius muscle

Branches 1.Tympanic branch-Forming lesser superficial

petrosal nerve to supply parotid

gland

2.Tonsillar branch

-Supply palatine tonsil

3.Lingual branch

-Supply posterior 3rd

of tongue

4.Muscle branch

-Supply stylopharyngeus

5.Pharyngeal branch-Share in pharyngeal plexus

1.Meningeal branch2.Auricular branch

3.Pharyngeal branch

4.Recurrent laryngeal branch supplying

-Mucosa of larynx

-All intrinsic muscles of larynx except

cricothyroid muscle (supplied by

external laryngeal nerve)

-Right recurrent laryngeal nerve

originates from right vagal nerve and

vice versa5.Superior and inferior cardiac

branches

6.Superior laryngeal nerve

Cranial part:-All muscles of palate except tensor

palate

-All muscles of pharynx except

stylopharyngeus

-All intrinsic muscles of larynx

Spinal part:

-Sternomastoid

-Trapezius

1.Muscular branches to all muscles oftongue except palatoglossus

2.Thyrohyoid and geniohyoid

muscles