A 9-year-old boy sustains a laceration of the lower eyelid from a dog bite. The wound lies just nasal to the inferior punctum and extends medially. On probing, the probe does not pass into the nasolacrimal duct. The structure most likely injured, and the key step in repair, are:

• A Inferior canaliculus; repair over a silicone bicanalicular stent ✓
• B Nasolacrimal duct; primary dacryocystorhinostomy
• C Orbital septum; layered closure without stenting
• D Tarsal plate only; delayed repair after 2 weeks

Explanation

The canaliculi lie in the medial third of the eyelids, so any laceration medial to the punctum must be assumed to involve them until probing proves otherwise. Failure of the probe to pass confirms canalicular transection. Repair requires microscopic identification of the cut ends and intubation with a silicone stent left in place for weeks to prevent cicatricial closure and lifelong epiphora. Primary DCR is irrelevant because the obstruction here is proximal, in the canaliculus.

Reference: AAO Basic and Clinical Science Course, Orbit, Eyelids, and Lacrimal System, 2023-2024 ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.