A 40-year-old woman who recovered from a complete right Bell's palsy six months ago now reports tearing from the right eye every time she eats. The mechanism responsible for this phenomenon is:

• A Regeneration of motor fibres of the buccal branch into the lacrimal gland
• B Regeneration of chorda tympani salivary fibres into the greater petrosal pathway to the lacrimal gland ✓
• C Loss of sympathetic innervation causing denervation hypersensitivity of the lacrimal gland
• D Reactivation of latent varicella zoster virus in the sphenopalatine ganglion

Explanation

Gustatory lacrimation, or crocodile tears, is a late sequela of proximal facial nerve injury. During aberrant regeneration, preganglionic parasympathetic fibres originally destined for the submandibular and sublingual glands via the chorda tympani are misdirected along the greater petrosal nerve to the pterygopalatine ganglion and onward to the lacrimal gland. Salivary stimuli such as chewing therefore trigger lacrimation. Motor fibre misdirection instead produces synkinesis, and VZV reactivation causes acute zoster, not delayed gustatory tearing.

Reference: Gray's Anatomy, 42nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.