Lacrimation is affected when facial nerve injury is at -

[Medicoman]

Lacrimation is affected when facial nerve injury is at -

• 1. Geniculate ganglion
• 2. In semicircular canal
• 3. At sphenopalatine gangila
• 4. None

EXP:

• First see the major symptoms of facial nerve palsy : -

1. Loss of lacrimation : - Due to involvement of greater superficial petrosal nerve.
2. Loss of stapedial reflex : - Due to involvement of nerve to stapedius.
3. Lack of salivation : - Due to chordatympani.
4. Loss of taste sensation from Anterior 2/3 of tongue : - due to chordatympani.
5. Paralysis of muscle of facial expression : - Due to terminal (peripheral) branches.

• Now you can make out the site of injury : -

• All the 5 symptoms (i to v) are present → Injury is at or proximal to geniculate ganglion (as all the branches of facial nerve are involved).

• There is no loss of lacrimation (greater superficial petorsal nerve is spared) but symptoms (ii) to (v) occur → Injury is distal to geniculate ganglion but proximal to or at the level of second genu from where the nerve to stapedius arises.

• Only symptoms (iii) to (v) are present (greater petrosal and nerve to stapedius are spared) → Injury is distal to second genu but proximal to origin of chorda tympani, i.e., Injury is between Second genu and mid portion of verticle segment.

• Only (vth) symptom is present → Injury is distal to the origin of chorda tympani, which may be at the level of stylomastoid foramen.