What Is Tarsal Tunnel Syndrome, and How Is It Different From Sciatica?

If you have ever felt a burning or electric sensation in the sole of your foot, especially at night, tarsal tunnel syndrome may be the cause. It is less well known than carpal tunnel syndrome in the wrist, but the mechanism is very similar. A nerve gets trapped inside a tight space, and the result is pain, tingling or numbness that can be hard to pin down.

What does tarsal tunnel syndrome feel like?

Tarsal tunnel syndrome typically causes burning, tingling or numbness in the sole of the foot, the heel or the underside of the toes. The symptoms often get worse after long periods of standing or walking and can flare up at night when you are resting.

Some people also notice that tapping the inner ankle with a finger reproduces the tingling. Clinicians call this a positive Tinel's sign, and it is one of the first things checked during a physical examination.

What causes tarsal tunnel syndrome?

Anything that increases pressure inside the tarsal tunnel can compress the tibial nerve. The tarsal tunnel is a narrow space formed by the bones of your ankle on one side and a tough band of tissue called the flexor retinaculum on the other. When this space gets crowded, the nerve has nowhere to go.

Overpronation is worth paying special attention to. If your foot rolls inward too far with every step, the tibial nerve is stretched repeatedly throughout the day. You can learn more about how foot position affects the whole chain in our guide to orthotics and overpronation.

How is tarsal tunnel syndrome different from sciatica?

The key difference is where the nerve is being compressed. In tarsal tunnel syndrome, the problem is local, right at the inner ankle. In sciatica, or more precisely lumbar radiculopathy, a nerve root in the lower back (often the S1 root) is irritated, and the pain travels all the way down the leg to the foot.

Both conditions can cause burning and numbness in the foot. But with sciatica you will usually feel pain or tightness starting in the buttock or back of the thigh, travelling down the calf before reaching the foot. With tarsal tunnel syndrome the symptoms are limited to the ankle and sole. Getting this distinction right matters, because the management path is completely different.

Sometimes both problems exist at the same time. A pinched nerve higher up can change the way you walk, shifting load onto the inner ankle and worsening a tarsal tunnel that was previously silent. This is why looking at the whole chain matters.

How is tarsal tunnel syndrome diagnosed?

Diagnosis usually starts with a clinical examination, including Tinel's sign (tapping the nerve behind the inner ankle bone to reproduce the tingling). From there, two main investigations are used.

• Nerve conduction studies (NCS). These measure how quickly electrical signals travel along the tibial nerve. Slowing at the tarsal tunnel confirms the entrapment.
• MRI of the ankle. An MRI can reveal cysts, swelling, varicose veins or other space-occupying structures inside the tunnel that are pressing on the nerve.

Why does foot posture matter in tarsal tunnel syndrome?

Foot posture matters because flat feet and overpronation are among the most common mechanical contributors to tarsal tunnel compression. When you lie down for a standard X-ray, gravity is removed. Your arch may look normal, and the inner ankle appears relaxed. It is only when you stand and bear your full body weight that the arch drops, the ankle rolls inward and the tunnel narrows.

A standing whole-body assessment using ScanAlign standing EOS imaging captures the foot and ankle under real load. It uses about 90% less radiation than a standard X-ray, around ten times less. The image also shows the whole alignment chain, from feet to pelvis, so your clinician can see whether a leg-length difference, pelvic tilt or knee angle is adding to the problem at the ankle.

This does not replace nerve conduction studies or MRI. It adds the postural context that those tests cannot show, helping clinicians understand why the nerve is being compressed, not just that it is.

What helps with tarsal tunnel syndrome?

Management depends on the underlying cause and severity. ScanAlign is a diagnostic imaging clinic, so we do not provide treatment. However, the options your clinician may discuss with you include the following.

• Orthotic support. Custom insoles that support the arch can reduce the inward roll of the ankle and take pressure off the tibial nerve.
• Activity modification and rest. Reducing activities that provoke symptoms, along with icing and elevation, can ease inflammation.
• Physiotherapy. Nerve-gliding exercises, calf stretching and ankle-strengthening work may help.
• Medication. Anti-inflammatory painkillers or nerve-specific medications are sometimes prescribed by your doctor.
• Injection or surgery. In persistent cases, a corticosteroid injection or surgical decompression of the flexor retinaculum may be considered by a specialist.

Seek urgent help if you develop sudden, severe weakness in your foot, loss of sensation that is spreading rapidly, or any loss of bladder or bowel control. These may indicate a more serious nerve problem. Contact your GP, call 111, or go to A&E.

Frequently asked questions about tarsal tunnel syndrome