A Morton's neuroma is a pathological condition which is caused by a benign neoplasm of the plantar interdigital nerve in the foot. This results from a tumorous growth of the perineurial tissue called a fibroma, thus a Morton's neuroma is not a true neuroma.
Although a Morton's neuroma most commonly arises in the 3rd interspace, between the 3rd and 4th metatarsal heads, it may also be found in the 2nd or 4th interspace as well.
Symptoms of a Morton's neuroma may include numbness, paraesthesia, and a sharp, shooting pain, which radiates towards the affected toes. This sensation is elicited or exaggerated by compressing the metatarsal heads together which, in turn, compresses the enlarged nervous structure.
Conservative care of a Morton's neuroma may include sclerosing and anti-inflamatory injections, as well accommodative orthosis. Although these methods may relieve painful and immobilizing neuroma conditions, surgical intervention may be required.
This involves soft tissue exposure or dissection of the enlarged nerve body. Once this is done, the neuroma must be isolated and removed by cutting away the stem, proximally, and the branches, distally.
Because the nerve is removed, there will be a loss of sensation in the affected area for several months or even years. Over time, this area will re-innervate by means of communicating branches from surrounding nerves.