A Morton’s neuroma is a condition that causes pain in the foot due to swelling or tumor of the small nerves of the foot.

Anatomy

The nerves of the foot run into the forefoot and out to the toes between the metatarsal bones of the feet. Once they reach the end of the metatarsals, they split and continue out to the end of the toes. Each nerve splits to supply sensation to half of two different toes. A Morton’s neuroma occurs just before the nerve splits into the two branches. The cause of the neuroma is not entirely understood but probably results from chronic injury to the nerve in this area. There are many theories of the cause of the chronic injury but none have been proven.

Symptoms

The neuroma usually causes pain in the ball of the foot with weight bearing. Many people with this condition report feeling a painful “catching” sensation while walking and many report sharp pains that radiate out to the two toes along the course of the involved nerve.

The diagnosis is usually made based on history and physical examination alone. X-rays are only useful to make sure the pain is not coming from some other cause such as a stress fracture. In some confusing cases, an injection of xylocaine and cortisone into the area can help decide of the diagnosis of a Morton’s neuroma is correct. The injection should result in a reduction of symptoms temporarily.

Treatment

Treatment of Morton’s neuroma usually begins with shoe adaptations. Sometimes simply moving to a wider shoe will reduce or eliminate the symptoms. New research shows locally injecting the nerve with a sclerosing agent may resolve the symptoms without surgery. Typically this involves a series of local injections over several weeks.

Surgery

If this fails to resolve the pain, surgery may be suggested. Surgery involves removing the neuroma, and since the neuroma is part of the nerve, the nerve is removed as well. This results in permanent numbness in the area supplied by the nerve.