Library · Cellular process
Rigor mortis
Make it clearer
Rigor mortis, or cadaveric rigidity, is the hardening of the body in the hours after death. What is happening is that the muscle stays contracted.
To understand it, you need to know that a muscle contracts when two proteins, actin and myosin, latch onto each other, and that releasing them takes energy. That energy is ATP, the currency the cell uses to pay for everything it does.
At death, ATP runs out. The membrane of the muscle fiber loses its seal and lets calcium in, and calcium is precisely the signal that latches actin onto myosin. The muscle contracts. But separating them again takes ATP, and there is none left: it is a contracted muscle that has lost the key to letting go.
The stiffness does not reach the whole body at once. It starts in heart muscle and then follows what looks like a path from the head toward the feet.
It sets in within hours and then eases on its own. The exact timing varies widely with the environment.
In brief
Rigor mortis is the stiffness that hardens the body after death.
It happens because ATP runs out and the muscle membrane lets calcium in.
Calcium binds actin and myosin, and without ATP that bond can no longer be released.
A contracted muscle that lost the key to let go.
It starts in heart muscle and follows an apparent progression from the head to the feet.
It sets in within hours and then eases, with timing that varies widely with the environment.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingPostmortem Changes, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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