What it feels like
The description people give is fairly consistent, and once heard it is recognisable:
- Burning, sharp or electric pain in the ball of the foot, radiating into two adjacent toes — most often the third and fourth.
- The sensation of standing on a small stone, a fold in the sock, or a marble under the ball of the foot.
- Numbness or tingling in the affected toes.
- Symptoms provoked by narrow or high-heeled shoes and by walking, and relieved by stopping, taking the shoe off and rubbing the foot — a very characteristic pattern.
- Occasionally a click that can be felt when the forefoot is squeezed.
There is typically no visible swelling and nothing to see, which is one reason people put up with it for a long time before mentioning it. OrthoInfo's Morton's neuroma page gives the orthopaedic account.
Why it develops
The nerve passes beneath a strong transverse ligament joining the metatarsal heads. Anything that compresses the space or increases movement between those bones irritates it repeatedly:
- Narrow toe boxes, which squeeze the metatarsal heads together around the nerve.
- Elevated heels, which shift load onto the forefoot and increase pressure at exactly that point.
- High-impact and repetitive activity — running, court sports, dance.
- Foot structure — hypermobility of the forefoot, a splayed forefoot, a bunion crowding the lesser toes, or a long second metatarsal.
- Existing forefoot deformity, which changes how load passes through the ball of the foot.
It is considerably more common in women, and footwear is the usual explanation offered for that difference.
Assessment
The diagnosis is mainly clinical. Squeezing the forefoot from side to side while pressing between the metatarsal heads reproduces the pain and sometimes produces a palpable click. Sensation in the affected toes is checked, and the alternatives are excluded — a stress fracture, capsulitis or synovitis of the joint at the base of a toe, a plantar plate tear, bursitis, or nerve symptoms referred from the ankle or the lumbar spine. Ultrasound or MRI may be used where the diagnosis is unclear or where surgery is being considered.
Getting the distinction right matters, because the treatments differ. Capsulitis of the second toe joint, for example, is a common mimic and does not respond to the same measures.
Management, in the usual order
Footwear change first, and it is not a token measure. A wide, deep toe box that lets the metatarsal heads spread, and a low heel that keeps load off the forefoot. For a proportion of people this alone substantially settles the symptoms, and no other intervention will work reliably while the aggravating shoe is still being worn.
Metatarsal padding or a metatarsal dome, placed just behind the metatarsal heads, lifts and separates them to decompress the nerve. Position is critical — a few millimetres too far forward and it makes matters worse — which is why it is worth having placed rather than guessed.
Activity modification. Reducing the aggravating impact activity for a period, substituting lower-impact exercise, and returning gradually.
Foot orthoses with a metatarsal addition, where there is an underlying mechanical contribution. See foot orthoses.
Injection therapy. Corticosteroid injection can give useful relief, particularly in smaller neuromas, though the benefit is not always durable and repeated injections carry risks including fat pad atrophy and skin depigmentation. Alcohol sclerosing injections are used in some centres.
Surgery is considered when conservative management over several months has failed. The usual procedure removes the affected segment of nerve, which relieves the pain but leaves permanent numbness in the web space and the adjacent sides of the two toes — a trade-off most people accept readily but which should be understood in advance. Decompression of the nerve without removing it is an alternative in some cases. Recurrence and persistent symptoms are possible.
Realistic expectations
Many people achieve satisfactory control with footwear change and padding alone and never need anything further. Others need injection, and a minority need surgery. What consistently does not work is continuing to wear the shoes that caused it while pursuing other treatments — that is the commonest reason a treatment plan appears to fail.
Symptoms that would change the picture and warrant prompt reassessment: numbness spreading beyond the two toes or affecting both feet, weakness, symptoms appearing in the other foot without an obvious cause, or night pain unrelated to activity. Those suggest a nerve problem originating elsewhere rather than a localised forefoot one. See when a foot problem needs professional care and, for related forefoot problems, bunions and hammertoes.