Nerve Supply of the Face 5th & 7th Neuroanatomy block-Anatomy-Lecture 7

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01 List the nuclei of the deep origin of the trigeminaland facial nerves in the brain stem.

02 Describe the type and site of each nucleus.

03 Describe the superficial attachment of trigeminaland facial nerves to the brain stem.

04 Describe the main course and distribution oftrigeminal and facial nerves in the face.

05 Describe the main motor & sensory manifestation incase of lesion of the trigeminal & facial nerves.

Color guide ● Only in boys slides in Green● Only in girls slides in Purple● important in Red● Notes in Grey

At the end of the lecture, students should be able to:

Objectives

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● Type: Mixed (Sensory & Motor).● Receive: sensory supply from the face (with an exception of a small area over ramus of

mandible by great auricular nerve C2,C3). ● Fibers:

● Nuclei (Deep origin): 3 Sensory + 1 Motor.

5th CN: Trigeminal Nerve

General somatic Afferent (Sensory): Special visceral Efferent (motor):

Mesencephalic nucleus

(Midbrain & pons)

Principal (main) sensory nucleus

(pons)

Spinal nucleus (pons, medulla & upper

2-3 cervical segments of spinal cord)

Motor nucleus (pons)

receives proprioceptive

fibers from muscles of

mastication.

receives touch fibers from

face & scalp.

receives pain & temperature sensations

from face & scalp.

supplies: 8 Muscles1) Four Muscles of mastication

(temporalis, masseter, medial & lateral pterygoid).

2) Other four muscles (Anterior belly of digastric, mylohyoid, tensor palati

& tensor tympani).

1. General somatic Afferent: ➔ Carrying general sensations from face and anterior part of the scalp.

2. Special visceral Efferent: ➔ Supplying muscles developed from the 1st pharyngeal arch, (8 muscles).

①

②

③

④

4

divisionEmerging

Divides into divisionsnucleus (dendrites of trigeminal ganglion):

1. Ophthalmic. CN V12. Maxillary. CN V23. Mandibular. CN V3

Emerges from the middle of the

ventral surface of the pons by 2 roots:

1. Large Lateral sensory root.

2. Small medial motor root.

● Axons of cells of motor nucleus join only the mandibular division.

5th CN: Trigeminal Nerve

Trig

emin

al

Gang

lion

Importance: Contains cell bodies : 1. Whose dendrites carry sensations from the face & scalp.2. Whose axons form the sensory root of trigeminal nerve.

Site:Occupies a depression in the

middle cranial fossa (apex of petrous temporal bone). (trigeminal impression)-(trigeminal cave).

Frontal: supplies skin of face & scalp.1

5

● Type: Pure sensory ● Divides: into 3 branches which pass through superior orbital fissure to the orbit:

Lacrimal: supplies skin of face & sensory for

lacrimal gland.

Nasociliary: supplies skin of face,

nasal cavity & eyeball.

Ophthalmic Division (CN V1)

2 3

Maxillary (CN V2) Mandibular (CN V3)

Type Pure sensory Mixed

Passes through Foramen rotundum Foramen ovale

Supplies

1. Upper teeth, gum & maxillary air sinus:➔ anterior, middle & posterior superior alveolar nerves.

2. Face: ➔ Zygomaticofacial nerve.

➔ Zygomaticotemporal nerve

➔ Infraorbital nerve.

Sensory branches:1. Lingual :

receives general sensations from anterior ⅔ the of tongue .

2. Inferior alveolar: supplies lower teeth, gums & face.

3. Buccal: supplies face (cheek on upper jaw).

4. Auriculotemporal: Supplies auricle, temple, parotid gland & TMJ.

Motor branches:

To 8 muscles (4 muscles of

mastication & other 4 muscles).

6

Maxillary & Mandibular Divisions (CN V2&3)

Maxillary (CN V2)

Mandibular (CN V3)

Trigeminal Neuralgia

7

❖ Compression, degeneration or inflammation of the 5th cranial nerve may result in a condition called trigeminal neuralgia or tic douloureux. (spasmodic contraction of the muscles in the face)

❖ This condition is characterized by:➢ recurring episodes of intense stabbing ➢ severe excruciating pain radiating from the angle of the jaw along a

branches of the trigeminal nerve.

❖ Usually involves maxillary & mandibular branches, rarely in the ophthalmic division.

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● Type: Mixed (Special Sensory, motor, Parasympathetic).

7th CN: Facial Nerve

Fibers

Special Visceral Afferent Special Visceral Efferent General Visceral Efferent

carrying taste sensation from anterior ⅔ of the

tongue.

supplying musclesdeveloped from the 2nd

pharyngeal arch.

Supplying parasympathetic secretory fibers to

submandibular, sublingual, lacrimal, nasal & palatine glands

Nuclei

Special Visceral Afferent (nucleus solitarius)

Special Visceral Efferent (motor nucleus of

facial nerve)

General Visceral Efferent(Superior salivatory nucleus)

receives taste from the anterior ⅔ of tongue.

supplies:1. Muscles of the face

2. Muscles of scalp, (Occipitofrontalis).

3. Muscles of the auricle. Posterior belly of digastric,

Platysma, Stylohyoid, Stapedius.

sends preganglionic parasympathetic secretory fibers to:

1. Pterygopalatine ganglion 2. Submandibular ganglion

Then the Postganglionic fibers pass to Sublingual, Submandibular,

Lacrimal, Nasal & Palatine glands.

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In fa

cial

can

al:

Greater petrosal nerve

Chorda tympani

carries preganglionic parasympathetic fibers to pterygopalatine ganglion then postganglionic fibers

to lacrimal, nasal & palatine glands.

carries:➔ Preganglionic parasympathetic fibers to

submandibular ganglion then postganglionic fibers to submandibular & sublingual glands.

➔ Taste fibers from anterior ⅔ of tongue.

7th CN: Course Of Facial NerveIt passes through internal auditory

meatus to the inner ear where it runs in facial canal.

Emerges from the stylomastoid foramen & enters the parotid gland

where it ends.

Emerges from the cerebellopontine angle by 2 roots:❶ ❷

Branches Of Facial Nerve

N.B. Geniculate ganglion: contains cell bodies of neurons; its fibres carrying

taste sensations from anterior ⅔ of tongue; ending in solitary nucleus in M.O .

Lies in internal acoustic meatus.

Nerve to stapedius Control the amplitude of sound waves from the external environment to the inner ear.

*Another pic in the next slide .

➔ Medial motor root: contains motor fibers➔ Lateral root (nervous intermedius): contains

parasympathetic & taste fibers.

❸

10

as it

em

erge

s fro

m th

est

ylom

asto

id fo

ram

en Posterior auricular

Muscular branches

Insi

de p

arot

id g

land

gives 5 terminal motor branches to the muscles of

the face

To occipitofrontalis muscle

To posterior belly of digastric & stylohyoid

★ Temporal★ Zygomatic★ Buccal★ Mandibular ★ Cervical

7th CN: Branches Of Facial Nerve

Bell’s Palsy

11

❏ Damage of the facial nerve results in paralysis of muscles of facial expressions: Facial (Bell’s) palsy;

also called lower motor neuron lesion (whole face affected)

NB. In upper motor neuron lesion (upper face is intact) (why? see next slide )

❏ Face is distorted:

Drooping of lower eyelid

Sagging of mouth angle

Dribbling of saliva

Loss of ➢ facial expressions➢ chewing➢ blowing➢ sucking

Unable to show teeth or close the eye on that side

Hyperacusis

Upper motor neuron lesion

12

Results from injury of the facial nerve fibers:

● In Internal acoustic meatus● In the middle ear● In the facial canal● In parotid gland.

Manifested by complete paralysis of facial muscles on the same side of lesion(Whole

face affection)

Lower motor neuron lesion

❏ This occurs after injury to the pyramidal tract (corticonuclear) above facial nucleus. ❏ Leads to paralysis of facial muscles of the lower ½ of face in the opposite side but the

upper ½ of the face intactbecause: ➔ Ms. of lower ½ of face receive pyramidal fibers from opposite cerebral cortex only➔ While Ms. of upper ½ of face receive pyramidal fibers from both cerebral hemispheres

(Bilateral representation).

Practice Q1: Trigeminal nerve divides into three divisions, motor nucleus join only in ?

A. CN V1

B. CN V2

C. CN V3

D. CN V1 & CN V3

Q2: Nasociliary supplies skin of face, nasal cavity and ?

A. Eyeball

B. Lacrimal gland

C. scalp

D. A&C

Q3: Which one of the following isn’t supplied by Maxillary nerve ?

A. Maxillary air sinus

B. Cheek on upper jaw

C. Zygomaticofacial nerve

D. Infraorbital nerve

Q4: Lesion of mandibular nerve may result in ?

A. Loss of general sensations of anterior 2/3 of tongue.

B. Loss of sensory supply of upper teeth.

C. Loss of sensation of skin over the nose.

D. Loss of lacrimation.

Q5: the posterior aulicular branch of the facial nerve supply:

A. Stylohyoid and Stapedius

B. occipitofrontalis muscle

C. posterior belly of digastric & stylohyoid

D. pterygopalatine ganglion

Q6: In bell palsy Hyperacusis is due to paralysis of which one of the following muscles?

A. Tensor Tympani

B. Tensor palati

C. Stapedius

D. Auricularis Superior

Q7: The special visceral efferent fibers of the facial nerve supplies:

A. submandibular, sublingual, lacrimal, nasal & palatine glands

B. anterior 2/3 of tongue

C. Muscles of the face

D. muscles developed from the 2nd pharyngeal arch

Q8 : Stimulation of which of the following nerves could lead to salivation and lacrimation?

A. Facial

B. Glossopharyngeal

C. Trigeminal

D. Vagus

Answers: Q1(C) Q2(A) Q3(B) Q4(A) Q5(B) Q6(C) Q7(D) Q8(A) 13

Girls team :

● Ajeed Al Rashoud● Taif Alotaibi● Noura Al Turki● Amirah Al-Zahrani● Alhanouf Al-haluli● Sara Al-Abdulkarem● Renad Al Haqbani● Nouf Al Humaidhi● Jude Al Khalifah● Nouf Al Hussaini● Rahaf Al Shabri● Danah Al Halees● Rema Al Mutawa● Amirah Al Dakhilallah● Maha Al Nahdi ● Razan Al zohaifi ● Ghalia Alnufaei

Boys team:

● Mohammed Al-huqbani● Salman Alagla● Ziyad Al-jofan● Ali Aldawood● Khalid Nagshabandi● Omar Alammari● Sameh nuser● Abdullah Basamh● Alwaleed Alsaleh● Mohaned Makkawi● Abdullah Alghamdi

Team leaders

● Ateen Almutairi● Abdulrahman Shadid

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