Definition

Tarsal tunnel syndrome is a condition in which the tibial nerve is being compressed. This is the nerve in the ankle that allows feeling and movement to parts of the foot. Tarsal tunnel syndrome can lead to numbness, tingling, weakness, or muscle damage mainly in the bottom of the foot.

Alternative Names

Tibial nerve dysfunction; Posterior tibial neuralgia; Neuropathy - posterior tibial nerve; Peripheral neuropathy - tibial nerve; Tibial nerve entrapment

Causes

Tarsal tunnel syndrome is an unusual form of peripheral neuropathy. It occurs when there is damage to the tibial nerve.

The area in the foot where the nerve enters the back of the inner side of the ankle is called the tarsal tunnel. This tunnel is normally narrow. When the tibial nerve is compressed, it results in the symptoms of tarsal tunnel syndrome.

Pressure on the tibial nerve may be due to any of the following:

• Swelling from an injury, such as a dislocated, sprained, or broken ankle
• An abnormal growth, such as a bone spur, lump in the joint (ganglion cyst), swollen (varicose) vein
• Flat feet or a high arch

Damage to the tibial nerve may result from body-wide (systemic) diseases, such as diabetes, low thyroid function (hypothyroidism), arthritis, or hereditary nerve problems. In some cases, no cause can be found.

Symptoms

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 at the ankle and in the bottom of the foot and toes
• Weakness and atrophy of foot muscles that move toes

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

Exams and Tests

Your health care provider will examine your foot 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 of toe extension

Tests that may be done include:

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

Other tests may include imaging tests, such as x-ray, ultrasound, or MRI.

Blood tests may be done to look for medical conditions that lead to nerve damage.

Treatment

Treatment depends on the cause of the symptoms.

• Your provider will likely suggest first resting, putting ice on the ankle, and avoiding activities that cause symptoms.
• Over-the-counter pain medicine, such as nonsteroidal anti-inflammatory drugs (NSAIDs), may help relieve pain and swelling.
• If symptoms are caused by a foot problem such as flat feet, custom orthotics or a brace may be prescribed.
• Physical therapy may help strengthen the foot muscles and improve flexibility.
• Steroid injection into the ankle may be needed.
• Surgery to enlarge the tarsal tunnel or transfer the nerve may help reduce pressure on the tibial nerve.

Outlook (Prognosis)

A full recovery is possible if the cause of tarsal tunnel syndrome 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 time.

Possible Complications

Untreated, tarsal tunnel syndrome 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)

When to Contact a Medical Professional

Contact your provider if you have symptoms of tarsal tunnel syndrome. Early diagnosis and treatment increases the chance that symptoms can be controlled.

References

Katirji B. Disorders of peripheral nerves. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 106.

Smith G, Shy ME. Peripheral neuropathies. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 392.