The anatomy of the forefoot includes 5 long bones that meet the bones of the toes. Between each of the long bones is a nerve that splits to innervate the corresponding two toes (inside of one, outside of the other). If there is friction or pressure on the nerve as it passes between the long bones, the nerve can become swollen and inflamed, creating a Neuroma.
The pain associated with Morton's Neuroma can be anything from a sharp shooting pang to a constant burn, throb or ache in the ball of the foot and/or 3rd and 4th toes. Due to the inevitable tightness across the forefoot when wearing shoes, often pain is exacerbated in shoes and relieved when barefoot, however this is not always the case if the neuroma is particularly large or the barefoot activity is particularly fierce.
A Morton's Neuroma is more likely to develop in women who use of tighter-fitting and / or high heeled shoes, or who have hypermobile feet with a collapsed metatarsal arch. Other contributing factors include high and low arched feet as well as those who have a wider foot structure with pre-existing toe deformities such as bunions and hammer toes.