The common peroneal nerve, often referred to as the common fibular nerve, is a major nerve that innervates the lower extremity. It is one of the two major branches off the sciatic nerve and receives fibers from the posterior divisions of L4 through S2 nerve roots.[1] The common peroneal nerve separates from the sciatic nerve in the distal posterior thigh proximal to the popliteal fossa.[1] After branching off of the sciatic nerve, it continues down the thigh, running posteroinferior to the biceps femoris muscle, and crosses laterally to the head of the lateral gastrocnemius muscle through the posterior intermuscular septum. The nerve then curves around the fibular neck before dividing into two branches, the superficial peroneal nerve (SPN) and the deep peroneal nerve (DPN).[1] The common peroneal nerve does not have any motor innervation before dividing; however, it provides sensory innervation to the lateral leg via the lateral sural nerve.[1] The superficial peroneal nerve innervates the lateral compartment of the leg, and the deep peroneal nerve innervates the anterior compartment of the leg and the dorsum of the foot.[2] These two nerves are essential in the eversion of the foot and dorsiflexion of the foot, respectively. The superficial peroneal nerve provides both motor and sensory innervation. The innervation of the superficial peroneal nerve appears below: Motor: Lateral compartment: Peroneus longus. Peroneus brevis.

Sensory: Anterolateral leg.
The deep peroneal nerve also provides both motor and sensory innervation in the leg. Deep peroneal nerve innervation is as follows: Motor: Anterior compartment: Tibialis anterior. Extensor hallucis longus. Extensor digitorum longus. Peroneus tertius.

Sensory: First dorsal webspace.
The following tests can quickly assess the common peroneal nerve and its respective branches for both motor and sensory functions: Sensory: Common peroneal nerve: lateral aspect of the leg just distal to the knee. Superficial peroneal nerve: the anterolateral distal third of the leg and the majority of the dorsum of the foot (except the first webspace). Deep peroneal nerve: first dorsal webspace.
Motor: Common peroneal nerve: none. Superficial peroneal nerve: eversion of the foot. Deep peroneal nerve: dorsiflexion of the foot and great toe extension.
This paper will focus on peroneal nerve injuries, including etiologies, epidemiology, history, and physical exam findings, as well as diagnosis and treatment.