A Morton's neuroma is a benign (noncancerous) swelling along a nerve in the foot that carries sensations from the toes. The reason the nerve starts to swell is unknown. But once swelling begins, the nearby bones and ligaments put pressure on the nerve, causing more irritation and inflammation. This produces burning pain, numbness, tingling and other abnormal sensations in the toes. A Morton's neuroma also is called an interdigital neuroma, intermetatarsal neuroma or a forefoot neuroma.
A Morton's neuroma usually develops between the third and fourth toes. Less commonly, it develops between the second and third toes. Other locations are rare. It also is rare for a Morton's neuroma to develop in both feet at the same time. The condition is much more common in women than men, probably as a result of wearing high-heeled, narrow-toed shoes. This style of shoe tends to shift the bones of the feet into an abnormal position, which increases the risk that a neuroma will form. Being overweight also increases the risk of a Morton's neuroma.