What Is a Neuroma?
A neuroma is a thickening of nerve tissue that may develop in various parts of the body. The most common neuroma in the foot is a Morton’s neuroma, which occurs between the third and fourth toes. It is sometimes referred to as an intermetatarsal neuroma. Intermetatarsal describes its location in the ball of the foot between the metatarsal bones. Neuromas may also occur in other locations in the foot.
The thickening of the nerve that defines a neuroma is the result of compression and irritation of the nerve. This compression creates enlargement of the nerve, causing the symptoms of Morton’s neuroma and eventually leading to permanent nerve damage.
Causes of Morton’s Neuroma
Anything that causes compression or irritation of the nerve can lead to the
development of a neuroma. One of the most common offenders is wearing shoes
that have a tapered toe box or high-heeled shoes that cause the toes to be forced
into the toe box. People with certain foot deformities—bunions, hammertoes,
flatfeet or more flexible feet—are at higher risk for developing a neuroma. Other
potential causes are activities that involve repetitive irritation to the ball of the foot,
such as running or court sports. An injury or other type of trauma to the area may
also lead to a neuroma.
Symptoms of Morton’s Neuroma
If you have a Morton’s neuroma, you may have one or more of these symptoms
where the nerve damage is occurring:
• Tingling, burning or numbness
• A feeling that something is inside the ball of the foot
• A feeling that there is something in the shoe or a sock is bunched up
The progression of a Morton’s neuroma often follows this pattern:
• The symptoms begin gradually. At first, they occur only occasionally when wearing narrow-toed shoes or performing certain aggravating activities.
• The symptoms may go away temporarily by removing the shoe, massaging the foot or avoiding aggravating shoes or activities.
• Over time, the symptoms progressively worsen and may persist for several days or weeks.
• The symptoms become more intense as the neuroma enlarges and the temporary changes in the nerve become permanent.
Diagnosis of Morton’s Neuroma
To arrive at a diagnosis, the foot and ankle surgeon will obtain a thorough history of your symptoms and examine your foot. During the physical examination, the doctor attempts to reproduce your symptoms by manipulating your foot. Other tests or imaging studies may be performed.
The best time to see your foot and ankle surgeon is early in the development of symptoms. Early diagnosis of a Morton’s neuroma greatly lessens the need for more invasive treatments and may help you avoid surgery.