Morton's neuroma is a benign inflammation of the nerves (nerves carry feeling to and from the brain and rest of the body). It can effect any of the toes in the foot. However, it most often affects the nerves that run between the third and fourth or second and third toes.

Causes

Morton's neuroma is an inflammation caused by a buildup of fibrous tissue on the outer coating of nerves running to the toes. This fibrous buildup is a reaction to the irritation resulting from nearby bones and ligaments rubbing against the nerves. This irritation can be caused by:

• Wearing shoes that are too tight

• Wearing shoes that place the foot in an awkward position (e.g., high heels)

• A foot that is mechanically unstable

• Repetitive trauma to the foot (such as from sports activities like tennis, basketball, and running)

• Trauma to the foot caused by an injury (such as a sprain or fracture)

It is unusual for more than one Morton's neuroma to occur on one foot at the same time. It is rare for Morton's neuroma to occur on both feet at the same time.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. Risk factors for Morton's neuroma include:

• Sex: Female

• Wearing narrow and/or high-heeled shoes

• Obesity

• Injuries to the foot

• Activities that cause repetitive trauma to the foot (such as sports-related activities)

Symptoms

Symptoms of Morton's neuroma include the following sensations, usually between the third and fourth or (less often) second and third toes:

• Burning, pain, tingling, and numbness often shooting into the toes

• Discomfort that is worse while walking

• Feeling of a lump between the toes

• Symptoms are usually temporarily relieved when a person:

• • Takes off their shoes

• • Flexes their toes

• • Rubs their feet

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam. Initial diagnosis of Morton's neuroma is based on your description of the type and location of pain and discomfort in the foot. The diagnosis will be confirmed by:

• Physical exam of the foot, including:

• • Checking for mechanical abnormalities in the foot

• • Squeezing the side of the foot, doing so will usually cause pain when Morton's neuroma is present

• Examination of your shoes to:

• • Check for excess wear in parts of the shoe

• • Check to see whether the shoes are too tight

• If the diagnosis is still in doubt, an x-ray may be done to rule out another cause of the pain (e.g., fracture)

• An ultrasound may be used to visualize the neuroma

Treatment

Treatments may include:

Prevention

Steps to help prevent Morton's neuroma include:

• Avoid wearing tight and/or high-heeled shoes

• If you are obese, lose weight

• If you play sports, wear roomy, properly fitting athletic footwear

RESOURCES:

American College of Foot and Ankle Surgeons
http://www.acfas.org

American Podiatric Medical Association
http://www.apma.org

National Institute of Arthritis and Musculoskeletal and Skin Diseases
http://www.nih.gov/niams

References:

American College of Foot and Ankle Surgeons

The Merck Manual of Medical Information, Simon and Schuster; 2000.