Morton's neuroma, also called Morton's metatarsalgia, Morton's disease, Morton's neuralgia, Morton metatarsalgia, Morton nerve entrapment, plantar neuroma, or intermetatarsal neuroma is a benign (non-cancerous) growth of nerve tissue (neuroma) that develops in the foot, usually between the third and fourth toes (an intermetatarsal plantar nerve, most commonly of the third and fourth intermetatarsal spaces). It is a common, painful condition.
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.
Pain is usually increased by forefoot weight bearing activities (such as running), with narrow-fitting footwear, or with high heeled shoes. It is usually painful to firmly touch the affected region and, in chronic cases, pain and sometimes an audible click, may be heard when squeezing the foot and toes together with the hand. Often a localized area of swelling may be evident at the site of injury.
Negative signs include no obvious deformities, erythema, signs of inflammation, or limitation of movement. Direct pressure between the metatarsal heads will replicate the symptoms, as will compression of the forefoot between the finger and thumb so as to compress the transverse arch of the foot. This is referred to as Mulder?s Sign. There are other causes of pain in the forefoot. Too often all forefoot pain is categorized as neuroma. Other conditions to consider are capsulitis, which is an inflammation of ligaments that surrounds two bones, at the level of the joint. In this case, it would be the ligaments that attach the phalanx (bone of the toe) to the metatarsal bone. Inflammation from this condition will put pressure on an otherwise healthy nerve and give neuroma-type symptoms. Additionally, an intermetatarsal bursitis between the third and fourth metatarsal bones will also give neuroma-type symptoms because it too puts pressure on the nerve. Freiberg's disease, which is an osteochondritis of the metatarsal head, causes pain on weight bearing or compression.
Non Surgical Treatment
The best results are achieved with massage techniques that encourage spreading and mobilizing the metatarsal heads. Metatarsal spreading is one technique that can help reduce the detrimental effects of nerve compression. To perform this technique, pull the metatarsal heads (not just the toes) apart and hold them in this position to help stretch the intrinsic foot muscles and other soft-tissues. When this technique is combined with the use of toe spacers, it will be even more effective.
The ultimate success of a Morton?s neuroma treated surgically can be variable. In cases where the underlying problem is only an irritated nerve (a true Morton?s neuroma), then surgery will probably be curative (although it may take a few months for the foot to fully heal). But in many cases, forefoot pain is more complex. There may be an irritated nerve or two causing pain, but the real problem is often excessive loading of the lesser metatarsals. The generic term for this condition is metatarsalgia. When considering surgery, identifying and addressing these problems may lead to a better end result.
Wearing proper footwear that minimizes compression of the forefoot can help to prevent the development of and aggravation of a Morton's neuroma.