A body is retrieved from a canal. At autopsy, the lungs are ballooned and crepitant, water and weeds are found in the airways, and diatoms are detected in the femoral bone marrow on acid digestion. The most forensically significant finding distinguishing ante-mortem drowning from post-mortem submersion is:

• A Presence of sand and weeds in the bronchi
• B Ballooning of lungs with increased weight (>1800 g combined)
• C Washerwoman's hands (maceration of skin)
• D Diatoms in femoral bone marrow matching those in the drowning medium ✓

Explanation

Diatoms (siliceous algae) can only reach bone marrow via circulation if the heart is beating during submersion — they are absorbed through the alveoli into pulmonary veins and distributed systemically. Finding diatoms in bone marrow or distant organs (kidney, liver) that match the species composition of the drowning medium constitutes strong proof of ante-mortem drowning. Weeds, sand, and lung hyperinflation can occur in post-mortem submersion; maceration is a function of time in water, not cause of death.

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.