Duration — In temperate regions, rigor mortis usually lasts for two to three days. In northern India, the usual duration of rigor mortis is 24 to 48 hours in winter and 18 to 36 hours in summer. According to the investigations of Mackenzie, in Calcutta, the average duration is nineteen hours and twelve minutes, the shortest period being three hours, and the longest forty hours. In Colombo, the average duration is 12 to 18 hours. When rigor mortis sets in early, it passes off quickly and vice versa. In general, rigor mortis sets in one to two hours after death, is well developed from head to foot in about twelve hours. Whether rigor is in the developing phase, established phase, or maintained phase is decided by associated findings like marbling, right lower abdominal discolouration, tense or taut state of the abdomen, disappearance of rigor on face and eye muscles. If on examination, the body is stiff, the head cannot be fixed towards the chest, then in all probability, the death might have occurred six to twelve hours or so more before the time of examination.”