Rigor mois occurs due to: September 2008

Ans. C: Muscle of the body began to stiffen A few hours after the death, the joints of the body stiffen and become locked in place. This stiffening is called rigor mois. Depending on temperature and other conditions, rigor mois lasts approximately 24- 48 hours in winter and 18-36 hours in summer. The phenomenon is caused by the skeletal muscles paially contracting. The muscles are unable to relax, so the joints become fixed in place Rigor mois can be used to help estimate time of death. The onset of rigor mois may range from 1-2 hours, depending on factors including temperature (rapid cooling of a body can inhibit rigor mois, but it occurs upon thawing). Maximum stiffness is reached around 12-24 hours post moem. It first stas in involuntary muscles (myocardium) Eyelids, neck and jaw muscles are affected first, with the rigor then spreading to other pas of the body. The joints are stiff but after some time general tissue decay and leaking of lysosomal intracellular digestive enzymes will cause the muscles to relax.