Some sources claim that entrapment of the plantar nerve because of compression between the metatarsal heads, as originally proposed by Morton, is highly unlikely, because the plantar nerve is on the plantar side of the transverse metatarsal ligament and thus does not come in contact with the metatarsal heads. It is more likely that the transverse metatarsal ligament is the cause of the entrapment. Despite the name, the condition was first correctly described by a chiropodist named Durlacher, and although it is labeled a "neuroma", many sources do not consider it a true tumor, but rather a perineural fibroma (fibrous tissue formation around nerve tissue).
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.
People with Morton's neuroma usually complain of pain that can start in the ball of the foot and shoot into the affected toes. However, some people just have toe pain. There may also be burning and tingling of the toes. The symptoms are usually felt up the sides of the space between two toes. For example, if the nerve between the third and fourth long bones (metatarsals) of the right foot is affected, the symptoms will usually be felt up the right-hand side of the fourth toe and up the left-hand side of the third toe. Some people describe the pain that they feel as being like walking on a stone or a marble. Symptoms can be made worse if you wear high-heeled shoes. The pain is relieved by taking your shoe off, resting your foot and massaging the area. You may also experience some numbness between the affected toes. Your affected toes may also appear to be spread apart, which doctors refer to as the 'V sign'. The symptoms can vary and may come and go over a number of years. For example, some people may experience two attacks of pain in a week and then nothing for a year. Others may have regular and persistent (chronic) pain.
During the examination, your physician will feel for a palpable mass or a "click" between the bones. He or she will put pressure on the spaces between the toe bones to try to replicate the pain and look for calluses or evidence of stress fractures in the bones that might be the cause of the pain. Range of motion tests will rule out arthritis or joint inflammations. X-rays may be required to rule out a stress fracture or arthritis of the joints that join the toes to the foot.
Non Surgical Treatment
Anti-inflammatory drugs may be recommended to dull the pain and lessen swelling. Neuropathic pain medications such as the antionvulsants and / or antidepressants may be tried as well. Many are able to recover from this issue at home by icing the area, resting the feet, and by avoiding wearing narrow or tight shoes. If these remedies do not work to alleviate symptoms, the doctor may give special devices to separate the toes and avoid the squeezing of the nerve. Steroid injections may reduce pain and swelling. Surgery may be required if these do not help.
For severe or persistent pain, you may need surgery to remove the neuroma. Once the nerve is gone, you permanently lose feeling in the affected area. One alternative to surgery is to undergo neurolysis injections. These use chemical agents to block pain signals. Another alternative is to take a prescription pain reliever that alleviates nerve pain.