Overview
Morton's neuroma is an enlarged nerve that usually occurs in the third interspace, which is between the third and fourth toes. To understand Morton's neuroma further, it may be helpful to look at the anatomy of the foot. Problems often develop in the third interspace because part of the lateral plantar nerve combines with part of the medial plantar nerve here. When the two nerves combine, they are typically larger in diameter than those going to the other toes. Also, the nerve lies in subcutaneous tissue, just above the fat pad of the foot, close to an artery and vein. Above the nerve is a structure called the deep transverse metatarsal ligament. This ligament is very strong, holds the metatarsal bones together, and creates the ceiling of the nerve compartment. With each step, the ground pushes up on the enlarged nerve and the deep transverse metatarsal ligament pushes down. This causes compression in a confined space.
Causes
Morton's Neuroma is a caused by pressure, abnormal function/motion or an imbalance in the structure of the foot such as flat feet, that causes an abnormal pressure on the structures and the nerves in the ball of the foot. It most commonly affects the nerve that goes to the 2nd 3rd or 4th toes. The squeezing of the nerve from abnormal motion leads to a protective thickening of the sheath that protects the nerve. Symptoms of Morton's Neuroma often occur during or after activities that cause a sidewards squeezing of the ball of the foot or from pressure such as walking, standing, or playing sport. Since squeezing is a common cause of the condition, shoes such as pointed toes or high heels can often lead to a neuroma. Shoes that are constricting, even tight sneakers, can pinch the nerve between the toes, causing inflammation and pain.
Symptoms
You may initially experience a tingling sensation in the space between your toes, which gets worse over time. This leads to cramp in your toes and a sharp shooting or burning pain on the ball of your foot or at the base of your toes. The pain is often worse when walking or wearing shoes that press on the affected area. This is caused by irritation of the nerve between your toe bones (metatarsal bones). The tingling will eventually lead to pain, which can get worse over time. You may also experience cramping of your toes. The pain is usually felt as a sharp shooting or burning pain on the ball of the foot or at the base of the toes, which is often made worse when you're walking. Some people with Morton's neuroma feel anxious about walking or even placing their foot on the ground. The pain is likely to be more intense if you wear tight shoes, so wearing shoes that have more room in the toe area can help. Rubbing your foot may also lessen the pain.
Diagnosis
Metatarsal bones will be examined clinically, and often an x-ray will be taken to assess the particular case and ensure against other conditions, including fracture. When the foot is examined by a doctor, he may feel a characteristic ?click,? referred to as Mulder?s sign, and the interspaces between toe bones will often be tender. The doctor may put pressure on these areas to localize the site of pain and test for other conditions, including calluses or stress fractures. Range of motion tests will also be applied to rule out arthritis or joint inflammations. X-rays may be required to ensure there are no stress fractures or arthritis within the joints that join the toes to the foot. Tenderness in one or more metatarsal bones may imply a pre-stress fracture or stress-fracture. An ultrasound scan may be used to confirm diagnosis of Morton?s Neuroma, as x-ray will not detect the condition, (but can confirm that the bones are uninjured).
Non Surgical Treatment
Treatment for Morton?s Neuroma usually begins conservatively, with a change in lifestyle choices. People suffering from the condition may find pain relief by reducing activity levels, changing footwear, using orthopedic supports, reducing weight. Medications are also available to help relieve the pain of Morton?s Neuroma. Over-the-counter medications are sometimes very helpful in reducing pain and inflammation. Your health care provider can also provide you with anesthetic or corticosteroid injections. These help to numb the area affected by the neuroma, and reduce inflammation.
Surgical Treatment
Patients are commonly offered surgery known as neurectomy, which involves removing the affected piece of nerve tissue. Postoperative scar tissue formation (known as stump neuroma) can occur in approximately 20%-30% of cases, causing a return of neuroma symptoms. Neurectomy can be performed using one of two general methods. Making the incision from the dorsal side (the top of the foot) is the more common method but requires cutting the deep transverse metatarsal ligament that connects the 3rd and 4th metatarsals in order to access the nerve beneath it. This results in exaggerated postoperative splaying of the 3rd and 4th digits (toes) due to the loss of the supporting ligamentous structure. This has aesthetic concerns for some patients and possible though unquantified long-term implications for foot structure and health. Alternatively, making the incision from the ventral side (the sole of the foot) allows more direct access to the affected nerve without cutting other structures. However, this approach requires a greater post-operative recovery time where the patient must avoid weight bearing on the affected foot because the ventral aspect of the foot is more highly enervated and impacted by pressure when standing. It also has an increased risk that scar tissue will form in a location that causes ongoing pain.
Prevention
While Morton?s Neuroma has been an ongoing topic of clinical investigation, the condition is in some cases difficult to either treat or prevent. Experimental efforts involving the injection of muscle or bone with chemicals such as alcohol, as well as suturing, and covering affected areas with silicone caps have been attempted, with varying success.
Morton's neuroma is an enlarged nerve that usually occurs in the third interspace, which is between the third and fourth toes. To understand Morton's neuroma further, it may be helpful to look at the anatomy of the foot. Problems often develop in the third interspace because part of the lateral plantar nerve combines with part of the medial plantar nerve here. When the two nerves combine, they are typically larger in diameter than those going to the other toes. Also, the nerve lies in subcutaneous tissue, just above the fat pad of the foot, close to an artery and vein. Above the nerve is a structure called the deep transverse metatarsal ligament. This ligament is very strong, holds the metatarsal bones together, and creates the ceiling of the nerve compartment. With each step, the ground pushes up on the enlarged nerve and the deep transverse metatarsal ligament pushes down. This causes compression in a confined space.
Causes
Morton's Neuroma is a caused by pressure, abnormal function/motion or an imbalance in the structure of the foot such as flat feet, that causes an abnormal pressure on the structures and the nerves in the ball of the foot. It most commonly affects the nerve that goes to the 2nd 3rd or 4th toes. The squeezing of the nerve from abnormal motion leads to a protective thickening of the sheath that protects the nerve. Symptoms of Morton's Neuroma often occur during or after activities that cause a sidewards squeezing of the ball of the foot or from pressure such as walking, standing, or playing sport. Since squeezing is a common cause of the condition, shoes such as pointed toes or high heels can often lead to a neuroma. Shoes that are constricting, even tight sneakers, can pinch the nerve between the toes, causing inflammation and pain.
Symptoms
You may initially experience a tingling sensation in the space between your toes, which gets worse over time. This leads to cramp in your toes and a sharp shooting or burning pain on the ball of your foot or at the base of your toes. The pain is often worse when walking or wearing shoes that press on the affected area. This is caused by irritation of the nerve between your toe bones (metatarsal bones). The tingling will eventually lead to pain, which can get worse over time. You may also experience cramping of your toes. The pain is usually felt as a sharp shooting or burning pain on the ball of the foot or at the base of the toes, which is often made worse when you're walking. Some people with Morton's neuroma feel anxious about walking or even placing their foot on the ground. The pain is likely to be more intense if you wear tight shoes, so wearing shoes that have more room in the toe area can help. Rubbing your foot may also lessen the pain.
Diagnosis
Metatarsal bones will be examined clinically, and often an x-ray will be taken to assess the particular case and ensure against other conditions, including fracture. When the foot is examined by a doctor, he may feel a characteristic ?click,? referred to as Mulder?s sign, and the interspaces between toe bones will often be tender. The doctor may put pressure on these areas to localize the site of pain and test for other conditions, including calluses or stress fractures. Range of motion tests will also be applied to rule out arthritis or joint inflammations. X-rays may be required to ensure there are no stress fractures or arthritis within the joints that join the toes to the foot. Tenderness in one or more metatarsal bones may imply a pre-stress fracture or stress-fracture. An ultrasound scan may be used to confirm diagnosis of Morton?s Neuroma, as x-ray will not detect the condition, (but can confirm that the bones are uninjured).
Non Surgical Treatment
Treatment for Morton?s Neuroma usually begins conservatively, with a change in lifestyle choices. People suffering from the condition may find pain relief by reducing activity levels, changing footwear, using orthopedic supports, reducing weight. Medications are also available to help relieve the pain of Morton?s Neuroma. Over-the-counter medications are sometimes very helpful in reducing pain and inflammation. Your health care provider can also provide you with anesthetic or corticosteroid injections. These help to numb the area affected by the neuroma, and reduce inflammation.
Surgical Treatment
Patients are commonly offered surgery known as neurectomy, which involves removing the affected piece of nerve tissue. Postoperative scar tissue formation (known as stump neuroma) can occur in approximately 20%-30% of cases, causing a return of neuroma symptoms. Neurectomy can be performed using one of two general methods. Making the incision from the dorsal side (the top of the foot) is the more common method but requires cutting the deep transverse metatarsal ligament that connects the 3rd and 4th metatarsals in order to access the nerve beneath it. This results in exaggerated postoperative splaying of the 3rd and 4th digits (toes) due to the loss of the supporting ligamentous structure. This has aesthetic concerns for some patients and possible though unquantified long-term implications for foot structure and health. Alternatively, making the incision from the ventral side (the sole of the foot) allows more direct access to the affected nerve without cutting other structures. However, this approach requires a greater post-operative recovery time where the patient must avoid weight bearing on the affected foot because the ventral aspect of the foot is more highly enervated and impacted by pressure when standing. It also has an increased risk that scar tissue will form in a location that causes ongoing pain.
Prevention
While Morton?s Neuroma has been an ongoing topic of clinical investigation, the condition is in some cases difficult to either treat or prevent. Experimental efforts involving the injection of muscle or bone with chemicals such as alcohol, as well as suturing, and covering affected areas with silicone caps have been attempted, with varying success.