A resident is instructed to collect vitreous humour from a cadaver for postmortem biochemical analysis. Through which approach should the needle be introduced?

• A Puncture of the cornea at the visual axis
• B Scleral puncture at the lateral canthus, posterior to the limbus ✓
• C Trans-palpebral puncture through the upper eyelid into the orbit
• D Optic nerve sheath puncture at the apex of the orbit

Explanation

Vitreous is aspirated by introducing a fine needle through the sclera at the outer (lateral) canthus, just behind the limbus, directing it toward the centre of the globe. Corneal puncture destroys the eye and risks anterior chamber fluid admixture, giving misleading values. Orbital or optic sheath approaches yield retrobulbar tissue rather than vitreous. Slow aspiration avoids collapse of the globe and contamination, preserving the integrity of the specimen for potassium and other estimations.

Reference: Parikh's Textbook of Medical Jurisprudence, Forensic Medicine and Toxicology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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