Some sources claim that entrapment of the plantar nerve because of compression between the metatarsal heads, as originally proposed by Morton, is highly unlikely, because the plantar nerve is on the plantar side of the transverse metatarsal ligament and thus does not come in contact with the metatarsal heads. It is more likely that the transverse metatarsal ligament is the cause of the entrapment. Despite the name, the condition was first correctly described by a chiropodist named Durlacher, and although it is labeled a “neuroma”, many sources do not consider it a true tumor, but rather a perineural fibroma (fibrous tissue formation around nerve tissue).
Morton’s neuroma is an inflammation caused by a buildup of fibrous tissue on the outer coating of nerves. This fibrous buildup is a reaction to the irritation resulting from nearby bones and ligaments rubbing against the nerves. Irritation can be caused by Wearing shoes that are too tight. Wearing shoes that place the foot in an awkward position, such as 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.
The most common presenting complaints include pain and dysesthesias in the forefoot and corresponding toes adjacent to the neuroma. Pain is described as sharp and burning, and it may be associated with cramping. Numbness often is observed in the toes adjacent to the neuroma and seems to occur along with episodes of pain. Pain typically is intermittent, as episodes often occur for minutes to hours at a time and have long intervals (ie, weeks to months) between a single or small group of multiple attacks. Some patients describe the sensation as “walking on a marble.” Massage of the affected area offers significant relief. Narrow tight high-heeled shoes aggravate the symptoms. Night pain is reported but is rare.
The physician will make the diagnosis of Morton’s neuroma based upon the patient’s symptoms as described above in an interview, or history, and a physical examination. The physical examination will reveal exceptional tenderness in the involved interspace when the nerve area is pressed on the bottom of the foot. As the interspace is palpated, and pressure is applied from the top to the bottom of the foot, a click can sometimes be felt which reproduces the patient’s pain. This is known as a Mulder’s sign. Because of inconsistent results, imaging studies such as MRI or ultrasound scanning are not useful diagnostic tools for Morton’s neuroma. Thus the physician must rely exclusively on the patient’s history and physical examination in order to make a diagnosis.
Non Surgical Treatment
The most important factor in the treatment of Morton’s neuroma is changing footwear. Sometimes a cushioned dome pad can be worn inside the shoe and this helps spread the metatarsal heads and decrease pressure on the nerve. There are other products that can be worn between the toes with certain types of shoes or when the client is barefoot. These toe spacers will help reverse biomechanical patterns that aggravate the nerve compression. Massage can be helpful, but should not be performed with deep pressure between the metatarsal heads. Additional pressure in this region can aggravate the nerve compression and prolong the pathology.
If your pain continues despite several months of conservative treatment, your doctor may recommend surgery to remove the neuroma or to widen the space through which the affected nerve travels. These types of surgery often are done under local anesthesia. If your doctor removes a portion of the affected nerve along with the neuroma, you may develop permanent numbness between the toes.
Ensuring that shoes are well fitted, low-heeled and with a wide toe area may help to prevent Morton’s neuroma.