Nerve entrapment in the foot and ankle

What is nerve entrapment?

A nerve entrapment (also called a compression neuropathy) is irritation of a single nerve at a specific point along its path. It is different from peripheral neuropathy, which usually affects many nerves at once and often starts in both feet. The two can occur together, and people with neuropathy may be more vulnerable to entrapment.

Entrapment can come from something pressing on the nerve (a tight boot, a cyst, a bone spur, scar tissue), from the nerve being stretched (for example by foot position or an ankle sprain), or from swelling in a confined space.^[1,2]

1. 1Medial plantar nerve — inner two-thirds of the sole and the first three-and-a-half toes
2. 2Lateral plantar nerve — outer third of the sole and the fifth and half of the fourth toe
3. 3Calcaneal branches — the heel pad
4. 4Sural nerve — the outer border of the foot and heel
5. 5Superficial peroneal (fibular) nerve — most of the top of the foot
6. 6Deep peroneal (fibular) nerve — the web space between the big and second toes
7. 7Saphenous nerve — the inner border of the foot near the ankle

Common entrapment sites

Tibial nerve at the inner ankle

Compression in the tarsal tunnel behind the inner ankle bone can cause burning, tingling or numbness in the sole.^[5] See tarsal tunnel syndrome.

Baxter’s nerve beneath the heel

Compression of the first branch of the lateral plantar nerve can cause inner-heel pain that resembles plantar fasciitis. See Baxter’s nerve entrapment.

Medial plantar nerve in the arch

Irritation of this branch, seen most often in runners, typically causes pain along the inner arch that may spread toward the big toe.^[2] It is sometimes called “jogger’s foot.”

Deep peroneal nerve on the top of the foot

Compression of the deep peroneal (fibular) nerve on the top of the foot — sometimes called anterior tarsal tunnel syndrome — can cause pain over the top of the foot and numbness in the web space between the big and second toes. Tight shoe laces or straps, bone spurs on the top of the foot and previous ankle injuries have all been implicated.^[4,2]

Superficial peroneal nerve at the lower leg and ankle

This nerve supplies most of the skin on the top of the foot. It can be irritated where it passes through the fascia of the lower leg, after ankle sprains, by tight boots, or after surgery near the front of the ankle.^[1]

Sural nerve on the outer ankle

The sural nerve runs behind the outer ankle bone and along the outer border of the foot. It can be irritated by scar tissue after ankle fractures or Achilles tendon surgery, or by pressure from footwear.^[1]

Saphenous nerve on the inner ankle

Less commonly, the saphenous nerve on the inner side of the lower leg and ankle is irritated, often after an injury or surgery in that area.

Common peroneal nerve at the knee

Although it sits outside the foot, compression of the common peroneal nerve near the outside of the knee can cause numbness on the top of the foot and weakness lifting the foot and toes. New weakness lifting the foot needs prompt evaluation.

Symptoms

Symptoms depend on which nerve is involved and may include:

• burning, tingling or “pins and needles” in a specific area of the foot
• numbness in that nerve’s territory
• shooting or electric pain, sometimes set off by tapping over the nerve
• pain that worsens with certain shoes, positions or activities
• less commonly, weakness of the muscles the nerve controls

How it’s evaluated

A careful evaluation aims to answer three questions: which nerve is involved, where it is being irritated, and why.

• History: the exact location and quality of symptoms, what triggers them, footwear, sports and work, previous injuries and operations.
• Examination: mapping of sensation, tapping along the nerve’s course, strength testing, foot and ankle alignment, and checks of circulation and the lower back, hip and knee.
• Imaging: X-rays can show bone spurs; ultrasound or MRI can show cysts, scar tissue or other structures pressing on a nerve.
• Nerve studies: EMG and nerve-conduction studies can help in some cases. They are usually performed by another specialist, and we coordinate this testing when it is needed.^[6]

Treatment options

Non-surgical care

• Remove the pressure: loosen or re-route laces, pad around tender areas, and change or modify boots, straps or shoes.
• Support and alignment: orthotics or bracing when foot position is stretching a nerve.
• Activity changes and physical therapy, including gentle nerve-gliding exercises.
• Medication for nerve pain, coordinated with your primary care physician or other clinicians.
• Injection in selected cases.

Surgery

When symptoms persist despite well-tried non-surgical care — or when a specific structure, such as a cyst or bone spur, is clearly compressing the nerve — surgery to release the nerve or remove the compressing structure may be discussed.^[3,1] Learn more about nerve decompression surgery.

Recovery and realistic expectations

Nerves recover slowly. Once the source of pressure is removed, pain often improves before numbness does, and recovery can continue for many months. The longer a nerve has been compressed, the less predictable recovery tends to be — one reason not to ignore persistent symptoms.

When to seek care

Consider an evaluation if burning, tingling, numbness or shooting pain in part of your foot lasts more than a few weeks, keeps recurring, or is getting worse — or if it began after an injury or operation.