A common fibular nerve injury can be confirmed by which of the following findings?

A common fibular nerve injury is often characterized by a specific condition known as "foot drop." This occurs because the common fibular nerve innervates muscles responsible for dorsiflexing the foot, such as the tibialis anterior. When this nerve is injured, the affected individual may have difficulty lifting the front part of the foot, which leads to the toes dragging during walking.

Additionally, this type of injury can also impact eversion of the foot and produce a sensory loss over the dorsum of the foot and the lateral aspect of the leg. However, the most definitive and classic presentation that signals a common fibular nerve injury is foot drop, making it the key finding for diagnosis.

The other potential symptoms listed, such as loss of sensation in the upper leg or thigh, are more associated with different nerve injuries, particularly the femoral nerve or lumbar plexus issues. Motor weakness in the arms would not typically relate to a common fibular nerve injury, as this nerve primarily affects lower limb function. Hence, foot drop serves as the hallmark indication of an injury to the common fibular nerve.