Tibial nerve entrapment — better known as tarsal tunnel syndrome — is a compression of the main nerve to the sole, as it passes behind the inner ankle. It causes burning pain, tingling, and numbness in the sole. So what is tarsal tunnel syndrome, and how do we treat it?

What is the tarsal tunnel?

foot diagram outlining medial plantar nerve

The tarsal tunnel is a narrow passage behind the inner ankle bone (the medial malleolus), roofed over by a band of tissue called the flexor retinaculum. The posterior tibial nerve runs through it, alongside tendons and blood vessels. Within or just beyond the tunnel, the nerve divides into three branches — the medial and lateral plantar nerves (to the sole) and the calcaneal nerve (to the heel).

When the nerve is compressed in this tunnel, the result is tarsal tunnel syndrome — essentially the foot’s version of carpal tunnel syndrome at the wrist.

What causes tarsal tunnel syndrome?

Anything that crowds the tunnel or stretches the nerve can cause it:

  • A ganglion cyst, a bony spur, or an enlarged tendon within the tunnel
  • Flat feet or a rolled-in (valgus) hindfoot, which stretches the nerve
  • A previous ankle fracture or sprain, or scarring
  • Swelling from conditions such as arthritis, or occasionally in pregnancy
  • Sometimes no clear cause is found

Symptoms of tarsal tunnel syndrome

Typical features include:

  • Burning, tingling, or numbness in the sole and toes
  • Aching pain around the inner ankle, sometimes radiating into the sole or up the inner leg
  • Symptoms worse with activity and standing, and often worse at night
  • A feeling of “walking on pebbles”

A useful sign is a positive Tinel’s sign — tapping over the nerve behind the inner ankle sends a tingle into the sole.

How is tarsal tunnel syndrome diagnosed?

Diagnosis combines the clinical picture with tests:

  • Examination — the Tinel’s sign and a dorsiflexion-eversion test (holding the foot up and out), which can reproduce the symptoms
  • Ultrasound — images the tibial nerve and any compressing cyst or spur, and guides an injection
  • MRI — shows the nerve and identifies a space-occupying cause such as a ganglion
  • Nerve conduction studies and EMG — assess the nerve and help confirm the diagnosis

Identifying a specific, treatable cause — such as a ganglion or spur — is an important part of the assessment.

How is tarsal tunnel syndrome treated?

Most cases settle with conservative treatment:

  • Orthotics and footwear — supporting a flat or rolled-in foot reduces the stretch on the nerve
  • Activity modification and physiotherapy — nerve-gliding exercises, calf and foot strengthening
  • Anti-inflammatories or nerve-pain medication — for symptom relief
  • Treating a specific cause — for example, draining a ganglion
  • Surgery — a tarsal tunnel release, reserved for persistent cases or a clear structural cause

Frequently asked questions about posterior tibial nerve entrapment 

What does tarsal tunnel syndrome feel like?

Burning, tingling, or numbness in the sole, often with an ache around the inner ankle, and sometimes a “walking on pebbles” feeling. It’s typically worse with activity and standing, and often worse at night. Tapping behind the inner ankle may send a tingle into the sole (a positive Tinel’s sign).

How is it different from plantar fasciitis?

Both cause symptoms in the sole and heel, but plantar fasciitis presents with sharp heel pain that worsens with the first steps of the morning, without nerve symptoms. Tarsal tunnel syndrome causes burning, tingling, or numbness — nerve symptoms — and a positive Tinel’s sign at the inner ankle. The nerve quality of the pain is the key difference.

What’s the difference between tarsal tunnel and jogger’s foot?

Jogger’s foot is entrapment of just the medial plantar branch of the tibial nerve, further into the arch — a more localised, distal version. Classic tarsal tunnel syndrome is compression of the whole posterior tibial nerve behind the inner ankle, affecting a wider area of the sole. They’re closely related, and jogger’s foot is sometimes considered a distal tarsal tunnel variant.

Can tarsal tunnel syndrome be cured without surgery?

Often, yes. Orthotics for a flat foot, physiotherapy, and — where needed — we perform an ultrasound-guided injection. Where there’s a specific cause, such as a ganglion or a bony spur, treating it helps. Surgery (a tarsal tunnel release) is reserved for persistent cases or a clear structural cause.

Final word from Sport Doctor London about tarsal tunnel syndrome

Tarsal tunnel syndrome is a compression of the posterior tibial nerve behind the inner ankle, causing burning pain, tingling, and numbness in the sole. The nerve-type symptoms and a positive Tinel’s sign distinguish it from plantar fasciitis. Most cases settle with orthotics, physiotherapy, and — where needed — an ultrasound-guided injection, with surgery reserved for stubborn cases or a clear structural cause.

If you have burning or tingling in the sole of your foot, Dr Masci can assess you in London, including ultrasound in clinic. Contact the team here or call +44 (0) 203 488 0350.

Other related foot and nerve conditions: