A case of complete decapitation in suicidal hanging : the mechanism and condition of decapitation.

Complete decapitation due to suicide by hanging is rare. We report the case of a decapitated man who was found in the sea near an estuary. A polyethylene rope was tied to the handrail of the bridge across a strait near the site of the body. The rope was 12 mm in diameter and 19 m in length from the handrail. It ended with a slip knot noose, and skin and mustache-like hair fragments were attached to it. The decapitated head was not found. The deceased weighed 82 kg and was 152 cm long without the head. The autopsy revealed coarse abrasions and intramuscular hemorrhage around the severed edge. The third cervical spine was not fractured. We reviewed the literature and suggested the conditions of body weight, fall height, rope diameter, and number of rolls in cases of decapitation by hanging. We calculated the hanging decapitation index (HDI) as the fall height (m) multiplied by the body weight (kg), divided by the rope diameter (mm), divided by the number of rolls ; and discussed the differences between complete and incomplete decapitation cases. J. Med. Invest. 70 : 290-293, February, 2023.