Tibial nerve dysfunction

Neuropathy - posterior tibial nerve; Tarsal tunnel syndrome

Tibial nerve dysfunction is an unusual form of peripheral neuropathy. It occurs when there is damage to the tibial nerve. This nerve is one of the lower branches of the sciatic nerve of the leg. It supplies movement and sensation to the calf and foot muscles.

A problem in function with a single nerve group, such as the tibial nerve, is called mononeuropathy. The usual causes are:

• Direct trauma
• Pressure on the nerve for a long period
• Pressure on the nerve from nearby body structures

Entrapment creates pressure on the nerve when it passes through a narrow structure.

The damage may destroy the myelin sheath that protects and insulates the nerve, or part of the nerve cell (the axon). This damage reduces or prevents the movement of signals through the nerve.

The tibial nerve is often injured by pressure from a ligament on the inner part of the ankle. Injury or disease of structures near the knee may also damage the tibial nerve. The tibial nerve may also be affected by diseases, such as diabetes, which damage many nerves.

In some cases, no cause can be found.

Symptoms may include any of the following:

• Sensation changes in the bottom of the foot and toes, including burning sensation, numbness, tingling, or other abnormal sensation
• Pain in the bottom of the foot and toes
• Weakness of foot muscles
• Weakness of the toes or ankle

In severe cases, the foot muscles are very weak and the foot can be deformed.

Your health care provider will examine your legs and ask about your symptoms.

During the exam, your provider may find you have the following signs:

• Inability to curl the toes, push the foot down, or twist the ankle inward
• Weakness in the ankle, foot, or toes

Tests for tibial nerve dysfunction may include:

• EMG (a recording of electrical activity in muscles)
• Nerve biopsy
• Nerve conduction tests (recording of electrical activity along the nerve)

Other tests that may be ordered include blood tests and imaging tests, such as ultrasound or MRI.

Treatment is aimed at restoring feeling and strength to the foot and toes. In some cases, no treatment is needed, and people will recover on their own. Severe loss of sensation may lead to toe or foot sores (ulcers) and infections.

Surgery to enlarge the tarsal tunnel or transfer the nerve helps reduce pressure on the tibial nerve. This may help some people.

Over-the-counter pain medicines may relieve mild pain. Other medicines may be prescribed to help control severe pain.

Physical therapy may help some people maintain muscle strength.

A change in job or retraining may be recommended.

A full recovery is possible if the cause of the tibial nerve dysfunction is found and successfully treated. Some people may have a partial or complete loss of movement or sensation. Nerve pain may be uncomfortable and last for a long period of time.

Untreated, tibial nerve dysfunction may lead to the following:

• Deformity of the foot (mild to severe)
• Movement loss in the toes (partial or complete)
• Repeated or unnoticed injury to the leg
• Sensation loss in the toes or foot (partial or complete)

Call your health care provider if symptoms of tibial nerve dysfunction are present. Early diagnosis and treatment increases the chance that symptoms can be controlled.

Prevention varies depending on the cause of the nerve damage.