Cranial nervesDr. ayat eldomouky

Names of cranial nerves Ⅰ Olfactory nerve Ⅱ Optic nerve Ⅲ Oculomotor nerve Ⅳ Trochlear nerve Ⅴ Trigeminal nerve Ⅵ Abducent nerve Ⅶ Facial nerve Ⅷ Vestibulocochlear

nerve Ⅸ Glossopharyngeal

nerve Ⅹ Vagus nerve Ⅺ Accessory nerve Ⅻ Hypoglossal nerve

Classification of cranial nerves Sensory cranial nerves: contain only afferent (sensory)

fibers◦ ⅠOlfactory nerve ◦ ⅡOptic nerve◦ Ⅷ Vestibulocochlear nerve

Motor cranial nerves: contain only efferent (motor) fibers◦ Ⅲ Oculomotor nerve ◦ Ⅳ Trochlear nerve ◦ ⅥAbducent nerve ◦ Ⅺ Accessory nerve◦ Ⅻ Hypoglossal nerve

Mixed nerves: contain both sensory and motor fibers--- ◦ ⅤTrigeminal nerve, ◦ Ⅶ Facial nerve,◦ ⅨGlossopharyngeal nerve◦ ⅩVagus nerve

Cranial Nerve I: Olfactory Arises from the olfactory epithelium in

upper part of nasal cavity. Passes through the cribriform plate of the

ethmoid bone Fibers run through the olfactory bulb and

terminate in the primary olfactory cortex Functions solely by carrying afferent

impulses for the sense of smell

Olfactory nerves

Olfactory nerve

Olfactory nerves

Olfactory bulb

Olfactory tracts

Cranial Nerve II: Optic Arises from the retina of the eye Optic nerves pass through the optic canals

and converge at the optic chiasma

Functions solely by carrying afferent impulses for vision

Cranial Nerve II: Optic

Figure II Table 13.2

Optic nerve

The optic canal

Optic chiasmsa

Cranial Nerve V: Trigeminal nerve: roots (large sensory and small motor)

Trigeminal ganglion

Trigeminal divisions

Branches Ophthalmic nerve

(Ⅴ1, purly sensory) leave the skull through the superior orbital fissure, to enter orbital cavity

Branches◦ Frontal nerve

Supratrochlear nerve Supraorbital nerve

◦ Lacrimal nerve◦ Nasociliary nerve Anterior ethmoidal Internal and external

nasal Infratrochlear Posterior ethmoidal ciliary

Maxillary nerve (Ⅴ2, sensory)

Leave skull through foramen rotundum

Branches◦ Infraorbital nerve◦ Zygomatic nerve◦ 3 Superior alveolar

nerve◦ Ganglionic

Pterygopalatine nerves

Mandibular nerve (Ⅴ3, mixed)

Leave the skull through the foramen ovale to enter the infratemporal fossa

BranchesPost. Division: 1. Auriculotemporal nerve2. Lingual nerve3. Inferior alveolar nerve◦ ant. Division: 1. Nerve of masticatory

muscles2. Buccal nerve

Mandibular nerve

Otic ganglion

Auriculotemporal nerve

Lingual nerve

Submandibular ganglion

Inferior alveolar nerve

Nerve to mylohyoid

muscle

Facial nerve

Roots : motor root

Sensory root(nervus

intermedius )

V111

internal acoustic meatus facial canal in inner ear stylomastoid foramen

Facial nerve in ear

Pterygopalatine ganglion

Roots :

•From the maxillary nerve which arises from the trigeminal ganglion

Sensory root

•From the greater petrosal nerve ( from the facial nerve)

parasympathetic root

•From the deep petrosal nerve ( from the nerve plexus around the internal carotid artery )

Sympathetic root

Branches:

1.orbital branches

2.nasal branches

3.palatine branches

4.pharyngeal branches

Facial nerve distribution

Greater petrosal nerve

Nerve to stapedius

Chorda tympani

Posterior auricular

nerve

Nerve to posterior belly of digastric muscle

Five terminal branches

Chorda tympani nerve

Cranial Nerve VIII: Vestibulocochlear Fibers arise from the hearing and

equilibrium apparatus of the inner ear, pass through the internal acoustic meatus,

Two divisions – cochlear (hearing) and vestibular (balance (equilibrium))

Cranial Nerve VIII: Vestibulocochlear

Figure VIII from Table 13.2

Cranial Nerve IX: Glossopharyngeal Fibers emerge from the medulla, leave the

skull via the jugular foramen, and run to the throat

Nerve IX is a mixed nerve with motor and sensory functions

Motor – innervates part of the tongue and pharynx, and provides motor fibers to the parotid salivary gland

Sensory – fibers conduct taste and general sensory impulses from the tongue and pharynx

Cranial Nerve IX: Glossopharyngeal

Figure IX from Table 13.2

Cranial Nerve X: Vagus

The only cranial nerve that extends beyond the head and neck

Fibers emerge from the medulla via the jugular foramen

The vagus is a mixed nerve Most motor fibers are parasympathetic

fibers to the heart, lungs, and visceral organs

Its sensory function is in taste Paralysis leads to hoarseness Total destruction incompatible with life

Cranial Nerve X: Vagus

Cranial Nerve XI: Accessory Formed from a cranial root emerging from

the medulla and a spinal root arising from the superior region of the spinal cord

The spinal root passes upward into the cranium via the foramen magnum

The accessory nerve leaves the cranium via the jugular foramen

Primarily a motor nerve ◦ Cranial root: Supplies fibers to the larynx,

pharynx, and soft palate◦ Spinal root: Innervates the trapezius and

sternocleidomastoid, which move the head and neck

Cranial Nerve XI: Accessory

Figure XI from Table 13.2

Cranial Nerve XII: Hypoglossal

Fibers arise from the medulla and exit the skull via the hypoglossal canal

Innervates both extrinsic and intrinsic muscles of the tongue except palatoglossus, which contribute to swallowing and speech

If damaged, difficulties in speech and swallowing; inability to protrude tongue

Cranial Nerve XII: Hypoglossal

Figure XII from Table 13.2

Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves

Work sheet: Cranial Nerves• Special Sense Nerves

–I,II,VIII•Motor Nerves

–Eye—III,IV,VI–Tongue—XII–Palate, pharynx,larynx---XI

• “Rest of body” nerves–IX,X– Face and jaws–VII, V

Sensory cranial nervesN. nerves Cranial exit Main action

I Olfactory cells Cribrifomforamina

Smell

II Optic nerve Optic canal Vision

VIII Vestibular ganglion Internal acoustic meatus

Equilibrium

Cochlear ganglion Hearing

Motor cranial nerves

N. Nerves Cranial exit Main action

III Occulomotor nerve Superior orbital fissure

Motot to most of extraoccular muscles

Parasympathetic to ciliary ganglion

IV trochlear nerve Superior orbital fissure

Motor to superior obliquus

VI Abducent nerve Superior orbital fissure

Motor to lateral rectus

XI Spinal accessory nerve

Jugular foramen sternocleidomastoid and trapezius

Cranial accessory nerve

Muscles of palate, pharynx and larynx

XII hypoglossal nerve Hypoglossal canal

Motor to muscles of tongue

Mixed cranial nervesN. nerves Cranial exit

V Trigeminal nerve,

Ophthalmic nerve

Superior orbital fissure

Maxillary nerve Foramen rotundum

Mandibular nerve

Foramen ovale

VI Facial nerve Internal acoustic meatus

IX Glossopharyngeal nerve Jugular foramen

X Vagus

Important nerves1. ophthalmic nerve Begin: as one branch of trigeminal ganglion End: divided into 3 branches enter the orbit

through superior orbital fissure Branches:

A. lacrimal nerveB. Frontal nerve: end as supratrochleal and

supra orbital nervesC. Nasociliary nerve, give the following nerves; 1. anterior and posterior ethmoidal , 2. external and internal nasal3. infratrochlear nerve

Important nerves2. maxillary nerve Begin: as one branch of trigeminal ganglion End: pass through foramen rotundum then

enter the orbit and end as infraorbital nerve Branches:

A. zygomatic nerveB. ganglionic nerve C. Post. Superior alveolar nervesD. middle Superior alveolar nervesE. ant. Superior alveolar nervesF. Infraorbital nerve

Important nerves3. mandibular nerve Begin: as one branch of trigeminal ganglion End: enter the infratemporal fossa through the foramen

ovale then divided into ant. And post. Division Branches of trunk: nerve to medial pterygoid muscle Branches of ant. division:

1. Masseteric nerve2. Deep temporal nerve3. Buccal nerve4. Nerve to lateral ptrygoid muscle Branches of post. division:

1. Auriculotemporal nerve2. Lingual nerve3. Inferior alveolar nerve

Important nerves4. lingual nerve Begin: as one branch of post. Division of

mandibular nerve End: descend medial to ramus of the mandible

then runs forward to the tongue Branches:

A. Carries general sensation of ant. 2/3 of the tongue

B. Joined with chorda tympani (branch of facial nerve) which carries taste sensation of ant 2/3 of tongue, also carries preganglionic parasympathetic fibers to sublingual and submandibular salivary glands

Important nerves5. inferior alveolar nerve Begin: as one branch of post. Division of

mandibular nerve End: enter the mandibular canal and

emerge from mental foramen as mental nerve

Branches: A. Sensory to the lower teethB. Nerve to mylohyoid muscleC. Mental nerve

Important nerves6. facial nerve Begin: the 7th crasnial nerve start as motor and

sensory roots End: enter parotid gland then divided into 5

branches Branches:

1. Grater petrosal nerve.2. Chorda tympanic nerve3. Nerve to stapedius4. Posterior auricular nerve5. 5 terminal: temporal, zygomatic, buccal,

mandibular and cervical branches

Important nerves6. hypoglossus nerve Begin: the last cranial nerve End: pass forward lateral to carotid sheath

to reach the tongue Branches:

Muscular branches to all muscles of the tongue except palatoglossus muscle

Parasympathetic ganglions1. pterygopalatine ganglion Site: pterygopalatine fossa Parasympathetic root (preganglionic):

greater petrosal nerve branch from facial nerve

Branches (postganglionic): 1. orbital branches 2. nasal branches 3. greater and lesser palatine branch4. pharyngeal branch

Parasympathetic ganglions2. 0tic ganglion Site: infratemoral fossa Parasympathetic root (preganglionic): lesser

petrosal nerve branch from glossopharyngeal nerve

Branches (postganglionic): Reach the parotid gland through auriculotemporal nerve

Parasympathetic ganglions3. submandibular ganglion Site: submandibular triangle Parasympathetic root (preganglionic):

chorda tympanic nerve branch from facial nerve

Branches (postganglionic): Reach the submandibular and sublingual glands

All muscles of mastication innervated by mandibular nerve

All branches of anterior division of mandibular nerve are motor except buccal nerve

All branches of posterior division of mandibular nerve are sensory except nerve to mylohyoid muscle

Important notes MCQ

The glossopharyngeal nerve is-------------1. Purely sensory2. Purely motor 3. Mixed nerve4. None of above

The facial nerve is--------------------1. Purely sensory 2. Purely motor3. Mixed nerve4. None of above

Ex. For important MCQ

The hypoglossal nerve is------------------1. Purely sensory2. Purely motor3. Mixed nerve

Which of the following nerve is the contiuation of the maxillary nerve -----------------

1. Lacrimal nerve2. Frontal nerve3. Nasociliary nerve4. Infraorbital nerve

The posterior division of mandibular nerve give rise to all of the following except

1. lingual nerve2. inferior alveolar nerve3. superior alveolar nerve4. auriculotemporal nerve

The posterior division of the mandibular nerve innervates which of the following muscles:

1. medial pterygoid muscle2. stylohyoid muscle3. mylohyoid muscle4. omohyoid muscle

chorda tympani nerve contains preganglionic parasympathetic fibers that synapse in……..

1. Pterygopalatine ganglion2. Otic ganglion3. Ciliary ganglion4. Submandibular ganglion

Greater petrosal nerve contains preganglionic parasympathetic fibers that synapse in……..

1. Pterygopalatine ganglion2. Otic ganglion3. Ciliary ganglion4. Submandibular ganglion

Lesser petrosal nerve contains preganglionic parasympathetic fibers that synapse in……..

1. Pterygopalatine ganglion2. Otic ganglion3. Ciliary ganglion4. Submandibular ganglion

Oculomotor nerve contains preganglionic parasympathetic fibers that synapse in……..

1. Pterygopalatine ganglion2. Otic ganglion3. Ciliary ganglion4. Submandibular ganglion

The trochelar nerve leaves the skull through…………1. Superior orbital fissure2. Foramen rotundum3. Foramen ovale4. Foramen spinosum  The accessory nerve leaves the skull through…………1. Superior orbital fissure2. Foramen rotundum3. Hypoglossal canal4. Jugular foramen

The mandibular nerve leaves the skull through…………1. Superior orbital fissure2. Foramen rotundum3. Foramen ovale4. Foramen spinosum

The vagus nerve leaves the skull through…………1. Superior orbital fissure2. Foramen rotundum3. Hypoglossal canal4. Jugular foramen  The spinal root of accessory nerve

innervates-----------1. Sternomastoid muscle2. Trapezius muscle3. Both a,b4. Neither a or b 

Which of the following nerves carry smell sensation from nasal mucosa

1. Lateral nasal nerve2. nasoplatine nerve3. sphenopalatine nerve4. olfactory nerve

Which of the following nerves carry visual sensation from the retina

1. Optic nerve2. Occulomotor nerve3. Trochlear nerve4. Abducent nerve

Which of the following statement concerning the lingual nerve is correct?

1. It contains parasympathetic postganglionic fibers.2. It contains special sensory (taste) fibers from

pos1/3 of tongue.3. It joins the chorda tympani nerve in the

infratemporal fossa.4. It is a branch of the facial nerve in the temporal

bone.

The following statements concerning the chorda tympani are correct except which?

1. It contains parasympathetic postganglionic fibers.2. It contains special sensory (taste) fibers.3. It joins the lingual nerve in the infratemporal

fossa.4. It is a branch of the facial nerve in the temporal

bone.

The branches of the posterior division of the mandibular nerve are sensory except:

1. Lingual nerve2. Inferior alveolar nerve3. Auriculotemporal nerve.4. Nerve to mylohyoid muscle.