A Mortons or interdigital neuroma is not a true neuroma but this is the term that is commonly used

A Mortons Neuroma is an impingement of the nerve, usually between the 3rd and 4th metatarsal heads. It's caused by a fibrosis around the nerve tissue, in this case it does get called a ‘neuroma’ even though it is not truly a neuroma. It is in females in their fourth to six decades, suggesting that smaller footwear might be part of the cause.

The main symptoms are usually shooting pains into the toes which gradually becomes worse, yet it is not at all times a shooting kind of pain at first. Symptoms may differ from one person to another with some just having a pins and needles in the toe, and some just a mild tingling to burning like pains. Eventually there is frequently an excruciating pain which can be present most of the time. Most commonly it is between the 3rd and 4th metatarsal heads, but can be seen in between any of them. Squeezing the ball of the foot from the sides can frequently produce the symptom and often a click may be felt with the finger of the other hand while compressing the ball of the foot. This is called a Mulder’s click.

What causes it is suspected to be an compression on the nerve by the adjacent metatarsal head, setting up a ‘pinched nerve’; the most apparent being using shoes which might be too tight over the ball of the feet. Additionally increased motion of the metatarsal heads may also be a factor, especially during sporting exercise. Obesity is also a frequent finding in individuals with a Morton’s neuroma.

Traditional treatment typically starts with advice on the right fitting of shoes and the use of metatarsal pads or domes. The shoes has to be wide enough to stop the pinching of the metatarsal heads and ideally have a lower heel height. If that's not useful, then a surgical removal of the neuroma is recommended. Occasionally the Mortons neuroma is treated with injection therapy to try and dissolve the neuroma and cryosurgery can also be occasionally tried.