Rigor mois occurs due to: September 2008
**Core Concept**
Rigor mortis is a temporary condition that occurs after death, characterized by stiffening of the muscles. This condition is caused by a series of biochemical changes that take place in the muscles after death.
**Why the Correct Answer is Right**
Rigor mortis occurs due to a complex interplay of biochemical reactions involving energy metabolism, ATP depletion, and changes in the muscle cell membrane. After death, the energy production in the muscle cells decreases, leading to a depletion of ATP. As a result, the actin and myosin filaments in the muscle cells slide past each other, causing the muscle fibers to contract. This contraction leads to the characteristic stiffness and rigidity of the muscles. The calcium ions in the muscle cells also play a crucial role in the process, as they help to trigger the contraction of the muscle fibers.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it doesn't provide a plausible explanation for the occurrence of rigor mortis.
* **Option B:** This option is incorrect because it's a nonspecific term that doesn't relate to the biochemical changes that occur in the muscles after death.
* **Option C:** This option is incorrect because it's a condition that occurs during life, not after death.
**Clinical Pearl / High-Yield Fact**
Rigor mortis typically begins within 2-4 hours after death and lasts for about 9-12 hours, after which the muscles begin to relax and become flaccid. This knowledge is useful in forensic medicine and death investigations.
**Correct Answer:** C.