An interdigital neuroma causes pain, swelling and nerve inflammation in the feet. "Interdigital" points to the location of the inflamed nerves, between the toes.
Usually this will be on the ball of the foot, between the the third and fourth toes. It may sometimes be found between the second and third toes, though this location is less common.
"Neuroma" is often a reference to a tumor but not in the case of an interdigital neuroma. Here it refers instead to a thickening around an interdigital nerve, which is a nerve that involves sensation in the areas between the toes.
These nerves run under a ligament in the forefoot. If bones and ligaments squeeze any of these nerves, fibrous tissue may build up. This thickening of an interdigital nerve can cause irritation and inflammation.
Interdigital neuroma also goes by the name Morton's neuroma. By either name, this condition causes burning, cramping, tingling, shooting pain and numbness.
A small lump may be felt between the bones, and the individual may feel like they have a stone in their shoe. As the thickened nerve slides between the bones, a click may be heard.
An injury to the foot from sports, a fracture or sprain, can cause interdigital neuroma. Repetitive motions like crouching or kneeling with toes hyperextended, can compress the nerves of the foot. Any activity that puts too much pressure on the forefoot, like jumping, running or even walking can be a factor.
High heels, or shoes with narrow toes, or shoes that fit poorly in any way, can make the condition worse. People with narrow feet or flat feet, or obese people, are more likely to develop a neuroma of this type.
Wearing comfortable, properly fitting shoes can help to prevent this condition, or to treat it once it has occured. Resting and staying off the feet can be quite helpful.
Exercises to stretch and strengthen the foot can ease symptoms. Use of electrical stimulation, massage, ultrasound, or whirlpool may bring some relief.
Arch support, or custom shoe orthotics can help protect the nerves. Orthotics are padded heels or insoles that correct improper alignment or function of the foot.