In a suspected case of death due to which of the following poison cadaveric rigidity lasts longer than usual?
**Core Concept**
Cadaveric rigidity, also known as rigor mortis, is a temporary stiffness of the body that occurs after death due to changes in the muscle tissue. It is a result of the energy depletion in the muscles, leading to the breakdown of adenosine triphosphate (ATP) and the subsequent contraction of the muscles.
**Why the Correct Answer is Right**
The duration of cadaveric rigidity varies depending on the cause of death. In cases where death is due to certain poisons, the body may exhibit a longer duration of rigor mortis. One such poison is **strychnine**, which acts by blocking the inhibitory neurotransmitter glycine at the spinal cord level, leading to an overactivation of the motor neurons and subsequent muscle contraction. This prolonged muscle contraction can result in a longer duration of cadaveric rigidity.
**Why Each Wrong Option is Incorrect**
**Option A:** **Opium** is a central nervous system depressant that slows down the respiratory and cardiac functions, leading to death. However, it does not cause prolonged cadaveric rigidity.
**Option B:** **Arsenic** is a poison that affects the cardiovascular and gastrointestinal systems. While it can cause various symptoms, it is not typically associated with prolonged cadaveric rigidity.
**Option C:** **Carbon monoxide** is a colorless, odorless gas that can cause tissue asphyxia by binding to the hemoglobin in red blood cells. It does not specifically cause prolonged cadaveric rigidity.
**Clinical Pearl / High-Yield Fact**
It's essential to note that the duration of cadaveric rigidity can also be influenced by environmental factors, such as temperature, and the presence of certain medical conditions. A thorough investigation is necessary to determine the cause of death and the duration of cadaveric rigidity.
**Correct Answer:** C. Strychnine.