Head and Neck
A patient with crocodile tears syndrome has spontaneous lacrimation during eating due to misdirection of regenerating autonomic nerve fibers. Which of the following nerves has been injured(AIIMS May 2012)
|A||Facial nerve proximal to the geniculate ganglion|
|B||Chorda tympani in the infratemporal fossa|
|C||Facial nerve at the stylomastoid foramen|
Crocodile tears syndrome: spontaneous lacrimation occurring parallel with the normal salivation of eating. It follows facial paralysis and is due to inaccurate regrowth of the regenerating nerve fibers into the wrong nerve sheaths, with some of those destined for the salivary glands going to the lacrimal glands.
Basically the nerve is damaged proximal to geniculate ganglion and the fibres destined to salivary glands & lacrimal glands are damaged. Then in a bid to repair the nerves, fibres regenerate, but are misdirected, sometimes. The salivary fibres move into chorda tympani but also into greater petrosal nerve. Hence, while salivation the tears also flow out.