American Board of Surgery Qualifying Exam (ABS QE) Practice Test

Which nerve is commonly affected by a fibula fracture?

1. Tibial nerve

2. Common peroneal nerve

3. Sural nerve

4. Femoral nerve

The correct answer is: Common peroneal nerve

A fibula fracture commonly affects the common peroneal nerve due to the anatomical location of the nerve in relation to the fibula. The common peroneal nerve wraps around the neck of the fibula, making it particularly vulnerable to injury in cases of fibular fractures. When the fibula is fractured, especially in the context of a lateral ankle injury, the proximity of the common peroneal nerve to the bony structures can lead to nerve compression or transection. This injury manifests clinically as weakness in dorsiflexion of the foot (foot drop) and sensory deficits on the lateral aspect of the lower leg and the dorsum of the foot, where the common peroneal nerve provides sensation. The other nerves mentioned do not have the same level of risk of injury associated with a fibula fracture. The tibial nerve, which innervates the posterior compartment of the leg and provides sensation to the sole of the foot, runs more medially and is less likely to be directly impacted by a fibular fracture. The sural nerve, providing sensation to the posterior-lateral aspect of the leg and lateral side of the foot, is also not typically affected in this injury pattern. The femoral nerve, responsible for the motor function