A stab wound to the anterior chest wall is measured as 2.5 cm wide with one sharp end, one squared-off end, a depth of 8 cm, and clean-cut margins without bruising. The MOST accurate inference about the weapon is:

• A Double-edged knife, 2.5 cm wide, at least 8 cm long
• B Scissor blade, because two separate sharp endings indicate a forked instrument
• C Single-edged knife, 2.5 cm wide, at least 8 cm long; squared end from blunt spine ✓
• D Broken glass fragment, approximately 2.5 cm long

Explanation

A stab wound with one sharp (angled) end and one squared/blunt end indicates a single-edged knife: the sharp end is produced by the cutting edge and the squared end by the blunt spine/back of the blade. Double-edged knives produce wounds with two sharp ends (fish-tail appearance). The weapon must be at least as long as the wound depth (8 cm minimum); the width approximates the blade width at the point of maximal penetration. Clean margins without bruising exclude blunt instruments.

Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.

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Written and medically reviewed by the StethoPrep medical team.