An execution-chamber electrocution produces a contact mark (Joule burn) at the scalp electrode site. The histology of this Joule burn is characterised by:

• A Full-thickness epidermal necrosis with peripheral leukocytic infiltration and fibrin deposition
• B Homogeneous coagulation necrosis identical to a thermal burn with no distinguishing features
• C Nuclear streaming ('palisading'), vacuolation of epidermal cells, and elongated basal cell nuclei oriented along current path ✓
• D Haemorrhage into the dermal papillae with preserved superficial epidermis

Explanation

Electrical skin marks (Joule burns, crocodile skin marks) have characteristic histological features: nuclear elongation and streaming (nuclei oriented in the direction of current flow — 'nuclear streaming'), vacuolation and vesiculation of basal and spinous layer cells, and a palisading arrangement of nuclei perpendicular to current. These changes result from electrothermal protein denaturation and cell membrane disruption during current flow. Unlike thermal burns, there is typically no inflammation in the acute phase; the changes are distinctive enough to diagnose electrical injury histologically even when no external mark is visible.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.