Portions of this article have appeared in the Intent Newsletter.
In 1876, Thomas G. Morton, a physician at Pennsylvania Hospital, misdiagnosed a benign tumor of the foot as an “affection of the fourth metatarsophalangeal joint.” Since then, his name has been associated with a condition that afflicts millions. While it is commonly referred to as “Morton’s neuroma,” for the purpose of this article we’ll use its more medical name, interdigital neuroma.
One cause of this problem is a structural combining of part of the lateral plantar nerve with part of the medial plantar nerve developing between the third and fourth metatarsals. When the two nerves combine, they are typically larger in diameter than those going to the other metatarsals. 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. The reason the nerve enlarges has not been determined, but like any soft tissue, it is vulnerable to pressure. For example, flat feet can cause the nerve to be pulled toward the middle (medially) more than normal, which can cause irritation and possibly enlargement of the nerve. The syndrome is more common in women than men, possibly because women wear confining shoes more often. High heels register more weight to be transferred to the front of the foot, and tight toe boxes create lateral compression. As a result, there is more force being applied in the area and the nerve compartment is squeezed on all sides. Under such conditions, even a minimal enlargement in the nerve can elicit pain.
A patient with pain at the ball of the foot will usually turn to a podiatrist. To diagnose interdigital neuroma, the podiatrist will palpate between the third interspace or pull the toes from side-to-side. The lesion is noticeable and painful when pressed. The podiatrist might try to elicit Muldor’s sign, holding the patient’s first, second, and third metatarsal heads with one hand and the fourth and fifth metatarsal heads in the other and pushing half the foot up and half the foot down slightly. In many cases of Morton’s neuroma, this causes an audible click, known as Muldor’s sign. Injectable steroids are often applied to reduce inflammation, and orthotics may be prescribed to help support the foot during gait. If these treatments fail, surgery is recommended.
Can the Massage Practitioner Help?
It is probably not uncommon for the massage therapist to see this condition in his or her practice. While massage of the leg and foot might be of considerable use to the patient, massaging the third interspace on the planter foot is often too painful for the patient. And, much like massage for bursitis, is contraindicated; massage to the lesion will most likely inflame the nerve. So how can the massage therapist help this condition?
Traditional treatments, while sometimes necessary, only mask the problem. A patient can only have so many cortisone shots before damage is done the tissues. Like any dysfunction in the body, the earlier it is treated, the better the long-term results. Interdigital neuroma is a nodule that, left untreated, will grow and become very painful. Once it grows in size, the chances of it receding are minimal. At an early stage, the surrounding space in the metatarsals must be increased to allow the nerve to heal. The first step in treatments, then, is to eliminate any day-to-day irritation to the foot. Tight-fitting shoes must be replaced with wide, comfortable shoes, and for professional women who must wear heels, this can be an issue. The flat-footed (pes-planus) patient might benefit from orthotics for arch support, but building the arch of the foot through specific exercises is a better choice.
The massage therapist can help create space between the metatarsals by specifically stretching them. For some people, stretching of the toes in this manner might be torturous at first, especially in women who wear high heels. For others, stretching of the foot and toes actually feels wonderful. It is necessary to stretch the webbing between the third and fourth metatarsals, as well as the other metatarsals. This is done by grasping both toes and spreading them apart in a repetition-based stretch. Since the lesion will most likely be sensitive, short holds with several sets of 8-10 are beneficial. To open the tissue on the plantar foot near the third interspace, one toe can be pulled up while the other is pulled down. This is an intense stretch that replicates the Muldor’s sign, so it is important to be gentle. The forefoot can be stretched by grasping the calcaneus with one hand, while the other gently rotates the ball of the foot. Again, the movements are repeated in sets.
There are several other stretches that can be performed for the toes, as well as stretches for the ankle and lower leg. In severe cases, the muscles of the hip should be examined also. Dysfunction in gait (i.e. pronation, supination) can irritate the neuroma and if its cause is not dealt with, the symptoms will persist. In severe cases, the patient might benefit from strengthening of the core muscles involving metatarsal and foot movement.
The most important thing to understand about treatment is that the patient must become proactive in healing the condition. The massage therapist can teach the patient how to stretch the metatarsals, ankle, and foot on a daily basis. If space is not created or “opened” before standing activity, the neuroma has little chance to heal. Simple, daily stretching, and if necessary, resistance exercises, are all part of the long term treatment plan. A neuroma is not something that goes away quickly; it can take a long period of time for it to heal. For massage therapists, incorporating these techniques into a practice can be extremely advantageous. Caught in an early stage, interdigital neuroma can be helped, and the massage therapist will begin to be known as a “specialist.”