Nerve Supply of the Face 5th & 7th

Neuroanatomy block-Anatomy-Lecture 7

Editing file Objectives

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

01 List the nuclei of the deep origin of the trigeminal and facial in the brain stem. 02 Describe the type and site of each nucleus. 03 Describe the superficial attachment of trigeminal and facial nerves to the brain stem. Color guide 04 Describe the main course and distribution of ● Only in boys slides in Green trigeminal and facial nerves in the face. ● Only in girls slides in Purple ● important in Red 05 Describe the main motor & sensory manifestation in ● Notes in Grey case of lesion of the trigeminal & facial nerves. 5th CN: Trigeminal ● 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:

1. General somatic Afferent: 2. Special visceral Efferent: ➔ Carrying general sensations from ➔ Supplying muscles developed from

face and anterior part of the scalp. the 1st pharyngeal arch, (8 muscles).

● Nuclei (Deep origin): 3 Sensory + 1 Motor. ① General somatic Afferent (Sensory): Special visceral Efferent (motor):

Spinal nucleus Mesencephalic Principal (main) (, medulla & upper Motor nucleus sensory nucleus nucleus 2-3 cervical segments (pons) (pons) (Midbrain & pons) of spinal cord) ④ supplies: 8 Muscles 1) Four receives (temporalis, masseter, medial & ② proprioceptive receives receives pain & lateral pterygoid). fibers from touch fibers from temperature sensations ③ muscles of face & scalp. from face & scalp. 2) Other four muscles (Anterior belly mastication. of digastric, mylohyoid, tensor palati & tensor tympani).

3 Site: Occupies a depression in the (apex of petrous temporal bone). (trigeminal impression)-(trigeminal cave).

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

5th CN: Trigeminal Nerve

Divides into divisions Emerges from nucleus (dendrites of the middle of the ): ventral surface of the pons by 2 roots: 1. Ophthalmic. CN V1 2. Maxillary. CN V2 1. Large Lateral Emerging 3. Mandibular. CN V3 sensory root. division ● Axons of cells of motor 2. Small medial nucleus join only the motor root.

mandibular division.

4 Ophthalmic Division (CN V1)

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

Frontal: Lacrimal: Nasociliary: supplies skin of face & scalp. supplies skin of face & sensory for supplies skin of face, 1 2 lacrimal gland. 3 nasal cavity & eyeball.

5 Maxillary & Mandibular Divisions (CN V2&3)

Maxillary (CN V2) Mandibular (CN V3)

Type Pure sensory Mixed Maxillary (CN V2) Passes Foramen rotundum Foramen ovale through

1. Upper teeth, gum & Sensory branches: Motor branches: maxillary air sinus: 1. Lingual : ➔ anterior, middle & receives general To 8 muscles posterior superior sensations from anterior (4 muscles of alveolar nerves. ⅔ the of tongue . mastication & other 4 2. Inferior alveolar: muscles). Mandibular (CN V3) 2. Face: supplies lower teeth, ➔ Zygomaticofacial gums & face. Supplies nerve. 3. Buccal: supplies face (cheek on upper jaw). ➔ Zygomaticotemporal 4. Auriculotemporal: nerve Supplies auricle, temple, parotid gland & TMJ. ➔ .

6 Trigeminal Neuralgia

❖ 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.

7 7th CN: ● Type: Mixed (Special Sensory, motor, Parasympathetic).

Fibers

Special Visceral Afferent Special Visceral Efferent General Visceral Efferent

carrying taste sensation supplying muscles Supplying parasympathetic from anterior ⅔ of the developed from the 2nd secretory fibers to tongue. pharyngeal arch. submandibular, sublingual, lacrimal, nasal & palatine glands

Nuclei

Special Visceral Afferent Special Visceral Efferent General Visceral Efferent (nucleus solitarius) (motor nucleus of (Superior salivatory nucleus) facial nerve)

receives taste from the supplies: sends preganglionic anterior ⅔ of tongue. 1. Muscles of the face parasympathetic secretory fibers to: 2. Muscles of scalp, 1. (Occipitofrontalis). 2. 3. Muscles of the auricle. Then the Postganglionic fibers pass Posterior belly of digastric, to Sublingual, Submandibular, Platysma, Stylohyoid, Stapedius. Lacrimal, Nasal & Palatine glands.

8 7th CN: Course Of Facial Nerve

Emerges from the cerebellopontine angle by 2 roots: Emerges from the ❶ ❷It passes through internal auditory ❸ ➔ stylomastoid foramen & Medial motor root: contains motor fibers meatus to the inner ear where it ➔ Lateral root (nervous intermedius): contains enters the parotid gland runs in . parasympathetic & taste fibers. where it ends.

Branches Of Facial Nerve *Another pic in the next slide .

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.

In facial canal: N.B. : contains cell bodies of neurons; its fibres carrying Control the amplitude of sound waves from Nerve to stapedius taste sensations from anterior ⅔ of the external environment to the inner ear. tongue; ending in in M.O . Lies in internal acoustic meatus.

9 7th CN: Branches Of Facial Nerve

Posterior auricular To occipitofrontalis muscle

To posterior belly of digastric Muscular branches & stylohyoid stylomastoid foramen as it emerges from the

★ Temporal gives 5 terminal motor ★ Zygomatic branches to the muscles of ★ Buccal the face ★ Mandibular ★ Cervical Inside parotid gland

10 Bell’s Palsy

❏ 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:

Unable to show teeth or Drooping of lower close the eye on that side eyelid

Sagging of mouth angle Loss of ➢ facial expressions ➢ chewing ➢ blowing ➢ sucking

Dribbling of saliva Hyperacusis

11 Lower motor neuron lesion

● In Internal acoustic meatus Manifested by complete Results from injury of the ● In the middle ear paralysis of facial muscles on facial nerve fibers: ● In the facial canal the same side of lesion(Whole ● In parotid gland. face affection)

Upper 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 intact because: ➔ 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).

12 Practice

Q1: Trigeminal nerve divides into three divisions, motor nucleus join only in ? Q5: the posterior aulicular branch of the facial nerve supply: A. CN V1 A. Stylohyoid and Stapedius B. CN V2 B. occipitofrontalis muscle C. CN V3 C. posterior belly of digastric & stylohyoid D. CN V1 & CN V3 D. pterygopalatine ganglion Q2: Nasociliary supplies skin of face, nasal cavity and ? Q6: In bell palsy Hyperacusis is due to paralysis of which one of the following muscles? A. Eyeball A. Tensor Tympani B. Lacrimal gland B. Tensor palati C. scalp C. Stapedius D. A&C D. Auricularis Superior Q3: Which one of the following isn’t supplied by ? Q7: The special visceral efferent fibers of the facial nerve supplies: A. Maxillary air sinus A. submandibular, sublingual, lacrimal, nasal & palatine glands B. Cheek on upper jaw B. anterior 2/3 of tongue C. C. Muscles of the face D. Infraorbital nerve D. muscles developed from the 2nd pharyngeal arch Q4: Lesion of may result in ? Q8 : Stimulation of which of the following nerves could lead to salivation and lacrimation? A. Loss of general sensations of anterior 2/3 of tongue. A. Facial B. Loss of sensory supply of upper teeth. B. Glossopharyngeal C. Loss of sensation of skin over the nose. C. Trigeminal D. Loss of lacrimation. D. Vagus

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

Team leaders

● Abdulrahman Shadid ● Ateen Almutairi Girls team : Boys team: ● Ajeed Al Rashoud ● Mohammed Al-huqbani ● Taif Alotaibi ● Salman Alagla ● Noura Al Turki ● Ziyad Al-jofan ● Amirah Al-Zahrani ● Ali Aldawood ● Alhanouf Al-haluli ● Khalid Nagshabandi ● Sara Al-Abdulkarem ● Omar Alammari ● Renad Al Haqbani ● Sameh nuser ● Nouf Al Humaidhi ● Abdullah Basamh ● Jude Al Khalifah ● Alwaleed Alsaleh ● Nouf Al Hussaini ● Mohaned Makkawi ● Rahaf Al Shabri ● Abdullah Alghamdi ● Danah Al Halees ● Rema Al Mutawa ● Amirah Al Dakhilallah ● Maha Al Nahdi Contact us: ● Razan Al zohaifi ● Ghalia Alnufaei Editing file most probably you don't need this