Three to four days after death, the skin over the abdomen and chest of an unrefrigerated corpse displays a network of branching, green-black lines following the course of the superficial veins. This appearance, called marbling, is produced by:
- A Diffusion of biliverdin from the gallbladder into the subcutaneous tissues
- B Bacterial haemolysis of vessels with formation of sulphhaemoglobin outlining the venous network ✓
- C Extravasation of hydrogen sulphide reacting with iron released from decomposing red cells in arteries
- D Postmortem proliferation of saprophytic fungi along dermal lymphatics
Correct answer: B. Bacterial haemolysis of vessels with formation of sulphhaemoglobin outlining the venous network
Explanation
Marbling appears around the third or fourth day when putrefactive bacteria haemolyse red cells within the superficial venous system; the pigment formed is sulphhaemoglobin, which stains the vessel walls and outlines them through the skin. Bile pigment diffusion produces generalised green discolouration but does not follow the venous tree, which is what kills option A as the best distractor.
Reference: Knight's Forensic Pathology, 4th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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