If a single spinal nerve is cut, the area of tactile loss is always greater than the area of loss of painful sensation, because
**Core Concept**
The question tests the understanding of spinal nerve anatomy and the differences in dermatome distribution for various sensory modalities, including **tactile sensation** and **painful sensation**. The **dermatome** map is crucial in clinical neurology for localizing lesions.
**Why the Correct Answer is Right**
Since the correct answer is not provided, let's analyze the general principle: when a single spinal nerve is cut, the area of tactile loss is indeed greater than the area of loss of painful sensation. This is because **painful sensation** has a greater degree of overlap between dermatomes compared to **tactile sensation**. This overlap ensures that even if one nerve is damaged, pain sensation can still be perceived due to the innervation from adjacent spinal nerves.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided, but generally, any option suggesting that tactile and pain sensation have the same dermatomal distribution would be incorrect.
**Option B:** Similarly, without the specific text, any option ignoring the concept of dermatomal overlap for pain would be wrong.
**Option C:** And any option that does not account for the specific sensory modalities' differences in dermatomal representation.
**Option D:** Without specifics, any option that does not consider the clinical implications of spinal nerve damage on sensory perception would be incorrect.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that the **dermatome map** is essential for clinical diagnosis, and understanding the differences in sensory modalities' distribution can help in localizing spinal lesions. The overlap of dermatomes for pain is more significant than for touch, which is a critical concept in neurology.
**Correct Answer:** Not provided in the query.