Which area is primarily affected by the L4 dermatome?

Which area is primarily affected by the L4 dermatome?

• A. Medial leg and foot including the medial malleolus
• B. Lateral thigh
• C. Anterior thigh
• D. Dorsum of foot

Answer: (A)

Dermatomes map sensory areas of the skin to spinal nerve roots. The L4 dermatome runs along the medial aspect of the leg and foot, extending to the medial malleolus. That medial-leg-to-foot region is the classic L4 distribution, making it the best match for the area described. The other regions correspond to different dermatomes: the lateral thigh and anterior thigh are typically L2–L3, and the dorsum of the foot is mainly L5.

Dermatomes map sensory areas of the skin to spinal nerve roots. The L4 dermatome runs along the medial aspect of the leg and foot, extending to the medial malleolus. That medial-leg-to-foot region is the classic L4 distribution, making it the best match for the area described. The other regions correspond to different dermatomes: the lateral thigh and anterior thigh are typically L2–L3, and the dorsum of the foot is mainly L5.