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Facial nerve and its disorders

Question
3 out of 33
 

Lacrimation is affected when facial nerve injury is at: [AIIMS Nov 12]



A GENICULATE ganglion

B In semicirculalr canal

C At sphenopalatine gangila

D At foramen spinosum

Ans. A Geniculate ganglion

For lacrimation greater superficial petrosal nerve which is a branch of facial nerve is responsible

It arises from the geniculate ganglion, / any lesion occurring at the level of geniculate ganglion will injure this branch and will lead to dryness of eyes.

Also Know

For locating the site of injury of facial nerve:

First see the major symptoms of facial nerve palsy:

i. Loss of lacrimation: Due to involvement of greater superficial petrosal nerve.

ii. Loss of stapedial reflex: Due to involvement of nerve to stapedius.

iii. Lack of salivatiion: Due to chorataympani.

iv. Loss of taste sensation from Anterior 2/5 of tongue: Due to chordatympani.

v. Paralysis of muscle of facial expression: Due to terminal (peripheral) branches.

Now you can make out the site of injury:

o All the 5 symptoms (i to v) are present: Injury is at or proximal to geniculate qanqlion (as all the branches) of facial nerve are involved)

o There is no loss of lacrimation (greater petrosal and nerve to stapedius are spread) but symptoms (ii) to (v) occur:

o Injury is distal to geniculate ganglion but proximal to or at the level of second genu from where the nerve to stapedius arises.

o Only symptoms (iii) to (v) are present (greater petrosal and nerve to stapedius are spread): Injury distal to second genu but proximal to origin of chorda tympani, ., Injury is between Second genu and mid portion of vertical segment.

o - Only (vth) symptoms is present: Injury is distal to the origin of chorda tympani, which may be at the level of stylomastoid foramen. .

Facial nerve and its disorders Flashcard List

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