A lesion in the paracentral lobule causes –
**Core Concept**
The paracentral lobule is a region in the brain involved in motor and sensory functions, particularly of the lower limbs. It is located near the central sulcus and is a part of the frontal and parietal lobes. Lesions in this area can affect the **corticospinal tract** and **somatosensory pathways**.
**Why the Correct Answer is Right**
A lesion in the paracentral lobule can cause lower limb weakness or paralysis due to its involvement in the **motor cortex**. The **somatosensory cortex**, also located in this region, can lead to sensory deficits when damaged. The specific symptoms depend on the exact location and extent of the lesion.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not directly relate to the typical symptoms caused by a lesion in the paracentral lobule.
**Option B:** Similarly, this option does not accurately describe the effects of such a lesion.
**Option C:** This option is also incorrect as it does not correspond to the known functions of the paracentral lobule.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that lesions in the paracentral lobule can cause **lower limb monoparesis**, which is weakness or paralysis of one leg. This is a critical clinical correlation for neurology and neurosurgery exams.
**Correct Answer:** D. Lower limb weakness