ANATOMY OF ANATOMY OF FACIAL NERVEFACIAL NERVE ANATOMY OF ANATOMY OF FACIAL NERVEFACIAL NERVE

DR.FAUZIADR.FAUZIA

Anatomy

• 7th cranial nerve• Facial nerve is a mixed nerve, having a motor

root and a sensory root.

Facial Nerve Nuclei

• 3 nuclei

1)Motor nucleus – lower pons below 4th ventricle

2)Parasympathetic (Superior salivatory ,lacrimal nucleus) – dorsal to motor N

3)Sensory /N of tractus solitarius

Anatomy: Course• Motor fibers originate…• Winds around…• Sensory roots• Emerge from the ant.surface of the brain b/w pons and med

obl• laterally in PCF with 8th nerve• Enters the IAM.• Then enters facial canal• Geniculate ganglion turns above the promontry.• In the middle ear cavity descend behind the pyramid • Emerges from the stylomastoid foramen• Finally divides into terminal branches.

Terminal branches

Bell’s Palsy

• one of the most common neurologic disorders affecting the cranial nerves.

• abrupt, unilateral, peripheral facial paralysis without a detectable cause.

Incidence:

• The incidence of Bell palsy in the United States is approximately 23 cases per 100,000 persons.

• Internationally: The incidence is the same as in the United States.

Demographics:

• Race: slightly higher in persons of Japanese descent.

• Sex: No difference exists • Age: highest in persons aged 15-45 years. Bell

palsy is less common in those younger than 15 years and in those older than 60 years.

Pathophysiology:

• Main cause of Bell's palsy is latent herpes viruses which are reactivated from cranial nerve ganglia

History:

• The palsy is often sudden in onset and evolves rapidly, with maximal facial weakness developing within two days.

• Associated symptoms may be decreased production of tears, and altered taste.

Physical exam:

• Bell's palsy causes a peripheral lower motor neurone palsy,

• which manifests as the unilateral impairment of movement in the facial muscles, drooping of the brow and corner of the mouth, and impaired closure of the eye and mouth.

Management, Eye care

• It focuses on protecting the cornea from drying and abrasion due to problems with lid closure and the tearing mechanism.

• Lubricating drops should be applied

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