A body recovered from a river has a spume (froth) from the nose and mouth, cutaneous lividity, waterlogging of the body, and 'washerwoman hands'. Diatom analysis of the bone marrow shows diatoms matching those of the river water. This finding of matching diatoms in bone marrow is MOST significant because:
- A It confirms that drowning was the cause of death by proving ante-mortem water inhalation with vital circulation ✓
- B It indicates that the body was submerged for over 72 hours allowing diatom diffusion
- C Diatoms are always found in bone marrow regardless of cause of death when submersion occurs
- D It proves homicidal drowning as diatoms cannot enter bone marrow naturally
Explanation
The diatom test is the most reliable laboratory test for drowning. Diatoms (siliceous algae) inhaled during active drowning pass through the alveolar-capillary barrier into the systemic circulation when the heart is still beating. Via circulation they reach and are deposited in protected sites such as bone marrow, liver, kidney, and brain — sites they cannot reach post-mortem by passive diffusion. Finding diatoms in bone marrow matching those of the drowning medium is strong evidence of vital immersion (drowning as cause of death). Bone marrow is specifically preferred as it is the most protected from postmortem contamination.
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.