Tarsal Tunnel Syndrome
A pinched nerve at the inner ankle causing foot pain and tingling
Quick Facts
- Type: Nerve compression (entrapment) disorder
- Location: Inner side of the ankle
- Main symptoms: Burning, tingling, numbness in the foot
- Often compared to: Carpal tunnel syndrome of the wrist
Overview
Tarsal tunnel syndrome occurs when the tibial nerve is squeezed or compressed as it travels through the tarsal tunnel, a narrow passage on the inner side of the ankle, bounded by bone and a band of tissue. The tibial nerve provides feeling and some movement to parts of the foot, so pressure on it causes pain and abnormal sensations.
It is similar in concept to carpal tunnel syndrome in the wrist, but it affects the ankle and foot. Symptoms often worsen with standing, walking, or activity and may ease with rest. Many cases improve with conservative treatment, although some require procedures to relieve the pressure on the nerve.
Symptoms
Symptoms occur on the inner ankle and the sole of the foot and may include:
- Burning, tingling, or a "pins and needles" sensation in the foot and toes
- Numbness in parts of the sole
- Aching or shooting pain that may radiate into the foot or up toward the calf
- A feeling of electric shocks
- Symptoms that worsen with standing, walking, or activity and improve with rest
- Symptoms that may be worse at night
Tapping over the nerve at the inner ankle can sometimes trigger tingling that shoots into the foot.
Causes
Anything that crowds or presses on the tibial nerve within the tarsal tunnel can cause the syndrome. Common causes include:
- Anatomy and foot shape: Flat feet or fallen arches, which change the stresses on the nerve.
- Swelling or masses: Cysts, swollen tendons, varicose veins, or bone spurs taking up space in the tunnel.
- Injury: Ankle sprains or fractures that cause swelling or scarring.
- Medical conditions: Diabetes, arthritis, and other conditions that cause swelling or affect the nerves.
In some cases, no specific cause is found.
Risk Factors
- Flat feet or other foot deformities
- Previous ankle injuries
- Diabetes or other conditions that affect nerves
- Inflammatory arthritis
- Activities or jobs involving prolonged standing or walking
- Conditions causing swelling in the legs and ankles
Diagnosis
Diagnosis combines the history and a physical exam of the foot and ankle. The clinician may tap over the nerve to check for tingling and assess sensation and strength. Tests may include:
- Nerve conduction studies and EMG: To confirm compression of the tibial nerve and assess its severity.
- Imaging: Ultrasound or MRI to look for cysts, masses, or other structures pressing on the nerve.
- Blood tests: To check for underlying conditions such as diabetes when relevant.
Treatment
Treatment usually starts with non-surgical measures.
- Rest and activity changes: Reducing activities that worsen symptoms.
- Orthotics and supportive footwear: Arch supports or custom inserts to relieve pressure, especially with flat feet.
- Anti-inflammatory medication: To reduce pain and swelling.
- Physical therapy and bracing: To support the ankle and improve mechanics.
- Injections: Corticosteroid injections may reduce inflammation around the nerve.
- Treating the cause: Removing a cyst or addressing an underlying condition.
- Surgery: If symptoms persist, a procedure to release the tissue and relieve pressure on the nerve may be recommended.
Prevention
- Wear well-fitting, supportive shoes and use arch supports if you have flat feet
- Treat ankle injuries promptly and complete rehabilitation
- Manage conditions such as diabetes and arthritis
- Avoid prolonged standing or repetitive strain where possible, and take breaks
- Maintain a healthy weight to reduce stress on the feet and ankles
When to See a Doctor
See a doctor if you have persistent burning, tingling, numbness, or pain on the inner ankle or sole of the foot, particularly if it interferes with walking or sleep or does not improve with rest and supportive footwear. Seek earlier evaluation if symptoms are worsening, if you notice weakness in the foot, or if you have diabetes, since untreated nerve compression can lead to lasting nerve damage.
Frequently Asked Questions
What does tarsal tunnel syndrome feel like?
It typically causes burning, tingling, or numbness on the inner ankle and sole of the foot, sometimes with shooting or electric-shock-like pain. Symptoms often worsen with standing, walking, or activity, may be worse at night, and tend to ease with rest.
Is tarsal tunnel syndrome like carpal tunnel syndrome?
Yes, the concept is similar. Both result from a nerve being compressed in a narrow tunnel: carpal tunnel affects the wrist and hand, while tarsal tunnel affects the inner ankle and foot. The symptoms of tingling, numbness, and pain are comparable in their respective areas.
Can tarsal tunnel syndrome go away without surgery?
Often, yes. Many people improve with rest, supportive footwear or orthotics, anti-inflammatory medication, physical therapy, and sometimes injections. Surgery to release the nerve is generally considered when symptoms persist despite these measures or when a specific cause needs removal.
What causes tarsal tunnel syndrome?
It is caused by pressure on the tibial nerve in the tarsal tunnel. Common contributors include flat feet, swelling, cysts or other masses, varicose veins, ankle injuries, arthritis, and diabetes. In some people, no specific cause is identified.
When should I worry about foot tingling and numbness?
See a doctor if foot tingling or numbness is persistent, worsening, interferes with walking or sleep, or is accompanied by weakness. Prompt evaluation is especially important if you have diabetes, since ongoing nerve compression can lead to lasting damage if untreated.
References
- American Academy of Orthopaedic Surgeons (OrthoInfo). Tarsal Tunnel Syndrome.
- MedlinePlus, U.S. National Library of Medicine. Tarsal tunnel syndrome.
- American College of Foot and Ankle Surgeons. Tarsal Tunnel Syndrome.
- National Institute of Neurological Disorders and Stroke (NINDS). Peripheral Neuropathy.