Where is the motor point of the peroneus longus located?

• A. Anterolateral surface of the lower leg
• B. Medial surface of the lower leg
• C. Posterior surface of the thigh
• D. Dorsum of the foot

Answer: (A)

Finding the motor point means locating the spot where the nerve fibers enter the muscle, so electrical stimulation produces a contraction with the least amount of current. For the peroneus longus, that entry point is on the anterolateral surface of the lower leg. The muscle sits in the lateral compartment and is innervated by branches of the superficial peroneal nerve that enter it from the anterolateral side in that region, making stimulation there most effective to evoke a response. The other sites don’t align with where the motor fibers actually enter peroneus longus: the medial lower leg would target different muscles or nerves, the posterior thigh is far away from this muscle, and the dorsum of the foot lies over extensors higher up or in different compartments.