RIGOR MORTIS: SUBJECT OF BODY AFTER DEATH: KAVINGNAR THANIGAI’S 651ST POST
Thanks: the Hindu .12th dec.2015 published
What causes rigor mortis to occur in a recently dead body?
In rigor mortis the muscles become stiff and rigid due to lack of energy production in the body after death. During life there is constant production of energy (ATP) in the body which is required for the routine activities of the muscle i.e. contraction and relaxation.
The muscle bundles in the body contain two important types of protein filaments, actin and myosin. In living state on nervous stimulation, hydrolysis of ATP occurs liberating energy which causes contraction of muscles with the formation of actomyosin complexes. The muscles relax due to dissociation of actomyosin complexes.
Hence for the regular muscular activity of a human being energy (ATP) is required. After death ATP production stops, the actomyosin complexes are not dissociated and hence the muscles lose their elasticity resulting in stiffening due to formation of viscid actomyosin complexes. Rigor mortis occurs both in voluntary and involuntary muscles. The actomyosin complex is broken down and the muscle becomes soft again due to decomposition late after death.
It has some relevance in determining the time since death. The muscles are flaccid immediately after death for about 3 to 6 hours before stiffening is detected; depending on the environmental temperature and other factors. There are a multitude of external and internal factors like age, nature of death, muscular state and atmospheric conditions that have remarkable interplay in the onset, duration of rigor mortis and the way rigor passes off from the corpse. Usually rigor mortis establishes throughout the body in 12 hours, stays in the body for another12 hours and disappears in the next 12 hours.
DR.R.SUDHA & DR.K.A.R.REDDY, Osmania medical college, Hyderabad