How can the common peroneal nerve be injured?

The common peroneal nerve can be injured through trauma to the fibular head and compression of the lateral aspect of the knee. This nerve runs closely along the fibular head, making it particularly susceptible to injury at this site. When there is direct trauma or compression, especially in conditions such as a knee dislocation or in certain positions that apply pressure to the lateral aspect of the knee, the common peroneal nerve can be entrapped or damaged.

In addition to direct trauma, this type of injury frequently occurs in situations where the lateral aspect of the knee is under stress, leading to possible neuropathy characterized by weakness in ankle dorsiflexion and sensory loss over the lateral aspect of the leg and dorsum of the foot.

Other options presented do not align with the typical mechanisms of common peroneal nerve injury. For instance, while a fracture of the femur could cause various neurologic injuries, it is less commonly associated with an isolated injury to the common peroneal nerve compared to trauma specifically at the fibular head. Options involving direct blows to the ankle or patellar dislocations are also not typical mechanisms for this nerve injury, as they do not involve the areas where the nerve is most vulnerable.