Tarsal Tunnel Syndrome


What and Where is the Tarsal Tunnel? 

The tarsal tunnel refers to a soft-tissue compartment behind and beneath the inside of your ankle through which some major tendons (the white cord in the diagram) and a major nerve (the yellow cord) pass.

The name of that major nerve illustrated to the left as the yellow cord is the Tibial Nerve, (or Posterior Tibial Nerve).  As you can see, as the nerve nears the foot, it divides into two terminal branches, the medial and lateral plantar nerves--the nerves that innervates the entire bottom of your foot.  

For more information about the nervous supply to the foot, please visit our web page on nerves.

What is Tarsal Tunnel Syndrome? 

Tarsal Tunnel Syndrome is a condition where that Posterior Tibial Nerve, becomes pinched and irritated as it passes underneath this soft-tissue tunnel.  This pinching of the nerve will usually cause the patient a great deal of discomfort.   

The condition of Tarsal Tunnel Syndrome found in the ankle is analogous to Carpal Tunnel Syndrome found in the wrist.

What factors cause Tarsal Tunnel Syndrome? 

Anything that results in pressure on the Posterior Tibial Nerve can create Tarsal Tunnel Syndrome.  For some examples, direct trauma to the ankle can do it, tendonitis of one of those tendons in the tunnel can cause it.  Varicose veins can cause it, as can any number of pathological growths in the region.  Tarsal Tunnel Syndrome seems to be more common with diabetes or rheumatoid arthritis.  

When abnormal amounts of pressure develop inside the tunnel, the nerve, who's sole reason for being is to feel things, does just that--it begins to feel that pressure.  And this is typically experienced by the patient as pain.  This is Tarsal Tunnel Syndrome. 

What are the symptoms of Tarsal Tunnel Syndrome?

There may be numbness, sensitivity or pain in the area where the nerve is being pinched, and in the areas of skin that the nerve would normally supply sensation to, (which is most of the bottom of the foot).  This is often a burning, electrical, tingling, pins and needles type of pain. 

Another common symptom is weakness in the muscles supplied the nerve supplies.

Symptoms are typically made worse by activity (which increases pressure in the Tarsal Tunnel), and are usually reduced by rest, though sometimes pain is severe at night.  

How is Tarsal Tunnel Syndrome diagnosed?

The diagnosis of tarsal tunnel syndrome can often be made by a good patient history and physical examination.  Neurological testing in the office is often all that's needed to make the diagnosis, though specialized testing known as Nerve Conduction Studies can test how well impulses are being carried up the nerve, and may be ordered.  Magnetic Resonance Imagine (MRI) may also be helpful in making the diagnosis.

How is Tarsal Tunnel Syndrome treated? 

To a large degree, it depends upon what mechanism is causing the problem, but the general aim is to decrease pressure on the nerve.  Rest, ice, elevation, anti-inflammatory medications, steroid injections, and physiotherapy may be helpful.  Custom-made, prescription, functional orthoses are usually helpful to address any biomechanical abnormality that may be causing this complaint (which his common).  Avoiding tight stockings and shoes may also provide relief.   

Surgery may be indicated, however, for difficult-to-resolve cases.  This surgery is usually done by decompressing the nerve, a procedure known as "neurolysis".  The procedure entails freeing up the nerve from any tissue that may be responsible for providing pressure to the nerve. 

Local, spinal or general anaesthesia may be used, though in most cases we prefer to use local.  Crutches are typically used post-operatively.

 

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The Achilles Foot Health Centre
S. A. Schumacher, D.P.M., F.A.C.F.A.S., F.A.C.F.A.O.M.  
Dr. S. A. Schumacher, Podiatric Corporation  

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