Multiple nerves supply the front, sides and back of the foot. These nerves can be pinched by joints, muscles and tendons within the foot, causing pain, numbness, and pins and needles. What are the most common causes of a pinched nerve in the foot, and how do we manage these conditions? 

Common causes of a pinched nerve in foot 

Pinched nerve in ball of foot: is it Morton’s neuroma?

Morton's neuroma on MRI

 

Morton’s neuroma is a thickening or swelling of the nerve between the small bones of your forefeet. We think the trapping is brought on by abnormal foot biomechanics and wearing the wrong footwear.

Generally, patients report pain at the sole, usually between the toes. Often, pain is described as a feeling of a stone in a shoe. Pain can be like an ache, sharp, or burning. Usually, excessive walking or running can cause worsening pain. Numbness or pins and needles radiating into the toes occur in some cases. Commonly, there is tenderness between the toes. In addition, a ‘Mulder’s’ click can be felt when squeezing the toes together.

It is essential to confirm a correct diagnosis with imaging. Ultrasound shows thickening and swelling of the nerve between the toes. In more complex cases, MRI is useful to rule out other causes of foot pain.

Pinched nerve in inner foot: Is it tarsal tunnel syndrome?

diagram of tarsal tunnel causing pinched nerve in foot

The tarsal tunnel is a space between the bottom of the long bone called the tibia and the inside of the Achilles tendon. It is covered by a tough retinaculum and contains nerves, vessels, and tendons.

Tarsal tunnel syndrome occurs when the posterior tibial nerve is compressed in the tarsal tunnel – similar to carpal tunnel syndrome in the wrist. Causes of compression include a ganglion cyst, arthritis spurs, extra muscles in the inside ankle, or twisting of the ankle.

Symptoms of tarsal tunnel syndrome include burning or shooting pain at the inside ankle and mid arch. Sometimes, numbness or pins and needles can occur in the inside arch.

Pinched nerve on outside of foot: Is it sural nerve entrapment? 

The sural nerve starts at the outer top part of the lower leg and travels down the calf close to the Achilles tendon. It winds around the outer part of the ankle to end at the outer part of the foot. It provides sensation (such as light touch) from the outer part of the lower leg to the outer part of the heel, ankle and foot.

Sural nerve damage leads to pain in the outer lower leg. Generally, pain is burning but could also be sharp shooting. Sometimes, pain radiates down into the outer part of the foot or up into the top part of the calf. Sural nerve pain is usually present at rest and is worsened by activity such as fast walking or running. Also, sitting or driving can worsen symptoms by increasing the tension on the sural nerve. People with sural nerve irritation have sensitivity to touch at the outer part of the calf and lower leg. Tapping the nerve at the trapping site will often cause a sharp. Your doctor will examine your calf and foot for evidence of sensitivity along the sural nerve. Other helpful tests include neural stretching tests such as slump or straight leg raise tests.

Investigations can help diagnose sural nerve pain. MRI scan might show inflammation of the nerve at the site of damage. However, most causes of sural nerve pain don’t demonstrate clear signs of inflammation and may be reported as normal. Generally, ultrasound is more useful as you can carefully follow the course of the nerve from the calf, looking for signs of nerve inflammation or trapping. Usually, nerve damage on ultrasound is seen as sudden nerve thickening at the trapping site.

Pinched nerve in heel: is it Baxter’s nerve entrapment?

Baxters nerve is a tiny nerve from a larger plantar nerve inside the ankle. This little nerve supplies the foot’s small muscles and sensation to the heel.

Baxters nerve entrapment presents similar to plantar fasciitis, but there are a few differences. Firstly, people describe sharp or burning pain inside the heel. Sometimes, the pain moves to the arch of the foot. You may feel pins and needles and have a numb heel. Unlike plantar fasciitis, you often don’t experience morning stiffness or pain. Finally, tenderness is slightly closer to the foot’s arch than plantar fasciitis. Nevertheless, Baxter’s neuropathy is confused with plantar fasciitis, often delaying the diagnosis.

In general, imaging such as ultrasound or MRI can give clues to the diagnosis. Sometimes, you can see the thickening of the minor Baxter’s nerve on the inside of the heel. Other times, you might see a normal plantar fascia scan, increasing suspicion of nerve trapping as the cause of pain. In severe cases, nerve trapping can cause the shrinking of the muscles on the outside of the foot, best seen on MRI. 

What does a pinched nerve in foot feel like?

Generally, a pinched nerve in the foot will lead to symptoms and signs that make us suspect pressure on the nerve. 

Common symptoms of a pinched nerve in the foot: 

  • sharp stabbing pain at the site of pinching
  • burning feeling in the area of the pinching 
  • numbness or pins and needles or both
  • a feeling that the foot falls asleep
  • Sometimes, unexplained pain may be due to a pinched nerve in the foot. 

Your doctor will examine you to see if the pinched nerve is coming from local pressure in the foot or referred from higher up, such as the spine. Pressing on the nerve at the pinching site often brings pain and symptoms.

How to get rid of pinched nerve in foot: 

Generally, we try simple measures before moving on to medications, injections and surgery. 

Conservative measures 

Firstly, you must avoid those activities causing the pinched nerve. For example, you should avoid running in tight-fitting shoes in Morton’s neuroma. Secondly, physiotherapy can help reduce the tension on pinched nerves. For example, manual therapy will help loosen the tissue around the sural nerve in the calf,  and ‘neural’ stretches and glides will reduce nerve tension. Finally, massage, acupuncture, and TENS can make the nerve less sensitive.

Medication 

duloxetine mediation for pinched nerve

If inflammation surrounds the nerve, topical and oral NSAIDs such as ibuprofen can help. Other tablets, such as amitriptyline and duloxetine, also known as nerve stabilisers, can reduce nerve sensitivity. Finally, capsaicin cream applied to the affected foot area reduces nerve symptoms.

Injections 

Overall, we use injections to reduce inflammation around a pinched nerve in foot. Generally, we use cortisone around a pinched nerve to reduce swelling and nerve symptoms. Moreover, ultrasound locates the trapping site and allows you to direct a small volume of cortisone where needed. Ultrasound improves accuracy and reduces the side effects of cortisone going to an unnecessary area. 

Surgery 

In cases that fail simple treatments, medication, and injections, we recommend surgery to reduce pressure on the nerve or excise it. Examples of where surgery can be effective include Morton’s neuroma, sural nerve entrapment, and Baxters nerve entrapment. However, surgery should only be performed if the diagnosis of a pinched nerve in the foot has been confirmed on imaging, nerve tests, or injections.

Other commonly asked questions:

Can a pinched nerve in back cause foot pain? 

Yes. One cause of nerve pain in the foot is a pinched nerve in the lumbar spine. You must see an experienced doctor to assess whether your foot pain is due to a local cause or if it is referred from the spine. 

Final word from Sportdoctorlondon about a pinched nerve in foot

Suspect a pinched nerve as a cause of unexplained pain in the foot, especially if imaging of the foot is normal. You need to see a doctor who is experienced in detecting nerve entrapment as a cause of foot pain. 

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