A common consequence of injury to the peroneal (fibular) nerve is what?

A common consequence of injury to the peroneal (fibular) nerve is what?

• A. Foot drop
• B. Plantar flexion weakness
• C. Knee flexion weakness
• D. Hip abduction weakness

Answer: (A)

Injury to the peroneal (fibular) nerve typically causes loss of dorsiflexion because this nerve, particularly its deep branch, supplies the muscles of the anterior compartment that lift the front of the foot. When dorsiflexion is weakened or lost, the foot cannot clear the ground during the swing phase, leading to foot drop and often a high-stepping gait to avoid dragging the toes. Plantar flexion, knee flexion, and hip abduction are governed mainly by other nerves—the tibial nerve for plantar flexion, the sciatic nerve branches for knee flexion, and the superior gluteal nerve for hip abduction—so they are not the typical or primary problems seen with peroneal nerve injury. Foot drop is the classic, most recognizable consequence.

Injury to the peroneal (fibular) nerve typically causes loss of dorsiflexion because this nerve, particularly its deep branch, supplies the muscles of the anterior compartment that lift the front of the foot. When dorsiflexion is weakened or lost, the foot cannot clear the ground during the swing phase, leading to foot drop and often a high-stepping gait to avoid dragging the toes. Plantar flexion, knee flexion, and hip abduction are governed mainly by other nerves—the tibial nerve for plantar flexion, the sciatic nerve branches for knee flexion, and the superior gluteal nerve for hip abduction—so they are not the typical or primary problems seen with peroneal nerve injury. Foot drop is the classic, most recognizable consequence.