What Causes Mortons Neuroma

Overview

Morton neuromaA morton’s neuroma (or an “inter-digital” neuroma) is found between the toes of the foot, most commonly the third and fourth toes. It can also occur between the metatarsal bones (the long bones in the forefoot). It is basically an entrapped nerve, which becomes inflamed due to constant irritation from the surrounding bony structures.

Causes

The cause of this problem is often due to impingement of the plantar nerve fibres between the metatarsal heads and the intermetatarsal ligament. It is entirely a biomechanical phenomenon. Differential diagnoses include stress fracture, capsulitis, bursitis or ligament injury at the metatarsal-phalangeal joint, a tendon sheath ganglion, foreign-body reaction and nerve-sheath tumour.

Symptoms

Episodes of pain are intermittent. Patients may experience 2 attacks in a week and then none for a year. Recurrences are variable and tend to become more frequent. Between attacks, no symptoms or physical signs occur. Two neuromas coexist on the same foot about 2-3% of the time. Other diagnoses should be considered when 2 or more areas of tenderness are present.

Diagnosis

In some cases your doctor will be able to feel the Morton’s as a swelling in the middle of your foot. However they may also suggest an X-ray or a blood test – this is normally to rule our other causes of the pain such as arthritis. The most accurate way to diagnose Morton?s itself is with magnetic resonance imaging (MRI) or ultrasound.

Non Surgical Treatment

Most patients’ symptoms subside when they change footwear to a wide soft shoe with a metatarsal support inside to relieve the pressure on the involved area. If this treatment fails, a cortisone injection into the nerve is occasionally helpful.interdigital neuroma

Surgical Treatment

Surgery to remove the neuroma may be recommended if more conservative treatment does not solve the problem. While surgery usually relieves or completely removes the symptoms, it often leaves a permanent numb feeling at the site of the neuroma.