What is the root level range for the lateral femoral cutaneous nerve?

What is the root level range for the lateral femoral cutaneous nerve?

• A. L2–L3
• B. L1–L2
• C. L3–L4
• D. L4–L5

Answer: (A)

This question tests which ventral rami contribute to the lateral femoral cutaneous nerve. It is formed mainly by the ventral rami of L2 and L3, with occasional input from L1, and not by L4–L5. The nerve then travels from the pelvis toward the lateral thigh, usually passing under the inguinal ligament near the ASIS to supply sensation to the outer thigh. Therefore, the root level range is L2–L3. While rare L1 contributions can occur, the standard range referenced in exams is L2–L3. This matters clinically because entrapment of this nerve under the inguinal ligament leads to meralgia paresthetica in the lateral thigh.

This question tests which ventral rami contribute to the lateral femoral cutaneous nerve. It is formed mainly by the ventral rami of L2 and L3, with occasional input from L1, and not by L4–L5. The nerve then travels from the pelvis toward the lateral thigh, usually passing under the inguinal ligament near the ASIS to supply sensation to the outer thigh. Therefore, the root level range is L2–L3. While rare L1 contributions can occur, the standard range referenced in exams is L2–L3. This matters clinically because entrapment of this nerve under the inguinal ligament leads to meralgia paresthetica in the lateral thigh.