What nerve injury is associated with a femoral shaft or lateral tibial plateau fracture?

• A. Radial nerve
• B. Sciatic nerve
• C. Peroneal nerve
• D. Median nerve

Answer: (C)

The main point is that the common peroneal (fibular) nerve is especially at risk with injuries near the knee and around the fibular head. It runs superficially around the neck of the fibula, so a fracture of the lateral knee area—such as a lateral tibial plateau fracture—or forces transmitted to that region, as can happen with a femoral shaft injury, can easily injure this nerve. When the peroneal nerve is damaged, you typically see foot drop from weakness of ankle dorsiflexion and toe extension, plus sensory loss over the dorsum of the foot and the first web space. This pattern fits better than injuries to the radial or median nerves (which are in the arm) or a pure sciatic nerve injury, making the peroneal nerve the most likely culprit in these fracture scenarios.