A 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.
The source of this pain is an enlargment of the sheath of an intermetatarsal nerve in the foot. This usually occurs in the third intermetatarsal space, the space between the third and fourth toes and metatarsals. It occurs here, at the site third intermetatarsal nerve, since this intermetatarsal nerve is the thickest being comprised of the joining of two different nerves. It also may occur in the other intermetatarsal areas, with the second interspace being the next most common location.
The symptoms of a Morton's neuroma are classic in nature. The patient complains of a burning , tingling, slightly numb feeling (dysesthesias) which radiates out to the toes on either side of the interspace that is involved. For instance, a Morton's neuroma of the third interspace will result in pain between the third and fourth toes, and a neuroma in the second interspace will cause pain between the second and third toes. The symptoms are usually aggravated by wearing shoes, particularly those with high heels. Symptoms are relieved by walking in flat, wide shoes or going barefoot. Rarely will the patient experience pain when sitting or laying down.
To diagnose Morton's neuroma the podiatrist commonly palpates the area to elicit pain, squeezing the toes from the side. Next he or she may try to feel the neuroma by pressing a thumb into the third interspace. The podiatrist then tries to elicit Mulder's sign, by palpating the affected interspace with one hand and squeezing the entire foot at the same time with the other hand. In many cases of Morton's neuroma, this causes an audible click, known as Mulder's sign. An x-ray should be taken to ensure that there is not a fracture. X-rays also can be used to examine the joints and bone density, ruling out arthritis (particularly rheumatoid arthritis and osteoarthritis).
Non Surgical Treatment
The first step in treating Morton's Neuroma is to select proper footwear. Footwear with a high and wide toe box (toe area) is ideal for treating and relieving the pain. The next step in treatment is to use an orthotic designed with a metatarsal pad. This pad is located behind the ball-of-the-foot to unload pressure, and relieve the pain caused by the neuroma.
If problem persists, consult your foot doctor.
Patients are commonly offered surgery known as neurectomy, which involves removing the affected piece of nerve tissue. Postoperative scar tissue formation (known as stump neuroma) can occur in approximately 20%-30% of cases, causing a return of neuroma symptoms. Neurectomy can be performed using one of two general methods. Making the incision from the dorsal side (the top of the foot) is the more common method but requires cutting the deep transverse metatarsal ligament that connects the 3rd and 4th metatarsals in order to access the nerve beneath it. This results in exaggerated postoperative splaying of the 3rd and 4th digits (toes) due to the loss of the supporting ligamentous structure. This has aesthetic concerns for some patients and possible though unquantified long-term implications for foot structure and health. Alternatively, making the incision from the ventral side (the sole of the foot) allows more direct access to the affected nerve without cutting other structures. However, this approach requires a greater post-operative recovery time where the patient must avoid weight bearing on the affected foot because the ventral aspect of the foot is more highly enervated and impacted by pressure when standing. It also has an increased risk that scar tissue will form in a location that causes ongoing pain.