What Is the Tarsal Tunnel?
The tarsal tunnel is a narrow space that lies on the inside of the ankle next to the ankle bones. The tunnel is covered with a thick ligament (the flexor retinaculum) that protects and maintains the structures contained within the tunnel—arteries, veins, tendons, and nerves. One of these structures is the posterior tibial nerve, which is the focus of tarsal tunnel syndrome.

What Is Tarsal Tunnel Syndrome?
Tarsal tunnel syndrome is a compression, or squeezing, on the posterior tibial nerve that produces symptoms anywhere along the path of the nerve. The posterior tibial nerve runs along the inside of the ankle into the foot.

Tarsal tunnel syndrome is similar to carpal tunnel syndrome, which occurs in the wrist. Both disorders arise from the compression of a nerve in a confined space.Although tarsal tunnel syndrome may not be as well known as carpal tunnel syndrome, it is nevertheless a cause of foot and ankle pain in adults.

Symptoms
Patients with tarsal tunnel syndrome experience one or more of the following symptoms:

The symptoms are typically felt on the inside of the ankle and/or on the bottom of the foot. In some people, a symptom may be isolated and occur in just one spot. In others, it may extend to the heel, arch, toes, and even the calf.

Sometimes the symptoms of the syndrome appear suddenly. Often they are brought on or aggravated by overuse of the foot—such as in prolonged standing, walking, exercising, or beginning a new exercise program.

It is very important to seek early treatment if any of the symptoms of tarsal tunnel syndrome occur. If left untreated, the condition progresses and may result in permanent nerve damage. In addition, because the symptoms of tarsal tunnel syndrome can be confused with other conditions, proper evaluation is essential so that a correct diagnosis can be made.

Causes
Tarsal tunnel syndrome is caused by anything that produces compression on the posterior tibial nerve, such as:

Diagnosis
The foot and ankle surgeon will examine the foot to arrive at a diagnosis and determine if there is any loss of feeling.During this examination, the surgeon will position the foot and tap on the nerve to see if the symptoms can be reproduced.He or she will also press on the area to help determine if a small mass is present.

Sometimes an MRI is ordered, usually if a mass is suspected or in cases where initial treatment does not reduce the symptoms. In addition, special studies used to evaluate nerve problems—electromyography and nerve conduction velocity (EMG/NCV)—may be ordered if the condition shows no improvement with non-surgical treatment.

Treatment
A variety of treatment options, often used in combination, are available to treat tarsal tunnel syndrome. These include:

This information has been prepared by the Consumer Education Committee of the American College of Foot and Ankle Surgeons, a professional society of 5,700 podiatric foot and ankle surgeons.Members of the College are Doctors of Podiatric Medicine who have received additional training through surgical residency programs. The mission of the College is to promote superior care of foot and ankle surgical patients through education, research and the promotion of the highest professional standards. Copyright © 2004, American College of Foot and Ankle Surgeons, www.acfas.org