**Question:** Meralgia paraesthetica is -

Core Concept: Meralgia paraesthetica is a clinical syndrome characterized by numbness, tingling, or pain in the lateral part of the thigh and knee due to compression or irritation of the lateral cutaneous nerve of the thigh (LCNT).

Correct Answer: Meralgia paraesthetica is **C**.

Why the Correct Answer is Right: Meralgia paraesthetica is a result of compression or irritation of the LCNT, which is a branch of the lateral femoral cutaneous nerve. This nerve supplies sensation to the lateral aspect of the thigh and knee. When the LCNT is compressed or irritated, it leads to the clinical symptoms described above.

Why Each Wrong Option is Incorrect:

A. Meralgia paresthetica refers to a condition characterized by numbness, tingling, or pain in the lateral part of the thigh and knee due to compression or irritation of the LCNT. Although similar, this question asks for the cause of the condition, not the condition itself.

B. This option is incorrect because it refers to a condition caused by compression or irritation of the femoral nerve, not the LCNT. The femoral nerve supplies sensation to the entire thigh, not just the lateral aspect.

C. This option is correct, as it describes the clinical syndrome characterized by numbness, tingling, or pain in the lateral part of the thigh and knee due to compression or irritation of the LCNT.

D. This option is incorrect because it refers to a condition caused by compression or irritation of the sciatic nerve, which supplies sensation to the lower limb, including the lateral aspect of the thigh and knee, but not specifically the LCNT.

Clinical Pearl: Meralgia paraesthetica is a clinical condition that should be considered in patients with symptoms of numbness, tingling, or pain in the lateral part of the thigh and knee. An accurate diagnosis can be made by physical examination, and treatment involves relieving the compression or irritation of the LCNT.