Common peroneal nerve

Common Peroneal Nerve

The common peroneal nerve (CPN), also known as the common fibular nerve, is a significant peripheral nerve of the lower leg that arises from the sciatic nerve. It is crucial for both motor and sensory functions in the lower extremities. The CPN innervates parts of the lower leg and foot, playing a pivotal role in movements such as foot eversion and dorsiflexion, and sensation to the upper part of the foot.

Anatomy

The common peroneal nerve is a branch of the sciatic nerve that bifurcates at the level of the knee. It travels laterally and inferiorly around the head of the fibula, where it is particularly vulnerable to injury due to its superficial location. The CPN divides into two terminal branches: the deep peroneal nerve and the superficial peroneal nerve. The deep peroneal nerve is responsible for the innervation of the anterior compartment of the leg, facilitating dorsiflexion of the foot and extension of the toes. The superficial peroneal nerve innervates the lateral compartment of the leg, controlling foot eversion and providing sensory innervation to the dorsum of the foot.

Function

The common peroneal nerve has both motor and sensory functions:

• Motor: It innervates the muscles of the anterior and lateral compartments of the leg, including the tibialis anterior, extensor digitorum longus, extensor hallucis longus, and the peroneal muscles. These muscles are essential for foot dorsiflexion, toe extension, and foot eversion.
• Sensory: It provides sensation to the skin of the upper lateral part of the foot and the lower part of the anterior leg.

Clinical Significance

Injury to the common peroneal nerve can result in a range of clinical manifestations, including foot drop, characterized by the inability to dorsiflex the foot, leading to a high-stepping gait to avoid dragging the foot on the ground. Causes of CPN injury include trauma, compression, or stretch injuries. The superficial location of the CPN near the head of the fibula makes it susceptible to injury from external forces.

Diagnosis and Treatment

Diagnosis of common peroneal nerve dysfunction typically involves a combination of clinical examination, patient history, and electrodiagnostic testing such as nerve conduction studies and electromyography. Treatment depends on the underlying cause of the nerve injury and may include physical therapy, orthotic devices to support the foot, or surgery in cases of severe injury or compression.

Prevention

Preventive measures for common peroneal nerve injury include avoiding prolonged pressure on the nerve, such as crossing legs frequently or wearing tight boots. Regular stretching and strengthening exercises for the lower extremities may also help reduce the risk of injury.