Rigor mortis starts in –
**Core Concept**
Rigor mortis is a post-mortem phenomenon characterized by the stiffening of muscles due to the accumulation of lactic acid and the depletion of ATP. This process involves the contraction of muscles, which can be attributed to the biochemical changes that occur after death.
**Why the Correct Answer is Right**
The correct answer is associated with the onset of rigor mortis, which typically begins 2-4 hours after death. This timing is related to the depletion of ATP stores in the muscles, which leads to the accumulation of lactic acid and the subsequent contraction of muscles. The specific time frame can vary depending on factors such as environmental conditions, the cause of death, and the physical condition of the individual.
**Why Each Wrong Option is Incorrect**
* **Option A:** This is incorrect because rigor mortis typically begins after 2-4 hours, not immediately after death. The initial stage of death involves a period of flaccidity, followed by the onset of rigor mortis.
* **Option B:** This is incorrect because the onset of rigor mortis is not instantaneous and occurs at a specific time frame after death.
* **Option C:** This is incorrect because the duration of rigor mortis is typically around 8-12 hours, not the onset of the process.
**Clinical Pearl / High-Yield Fact**
Rigor mortis can be influenced by environmental factors such as temperature, which can affect the rate of ATP depletion and the subsequent contraction of muscles.
**Correct Answer: A. 2-4 hours after death**