Metatarsalgia is caused by the compression of a small toe nerve between two displaced metatarsal bones. Inflammation occurs when the head of one displaced metatarsal bone presses against another and they catch the nerve between them. With every step, the nerve is pushed together by the bones and then rubbed, pressed again, and irritated without relief. Consequently, the surrounding nerve tissue becomes enlarged, with a sheath of scar tissue that forms to protect the nerve fibers.
Metatarsalgia really covers a group of foot disorders. The classic symptom is pain in the front (ball) of the foot. Many people say that it is "like walking on pebbles," but x-rays usually show nothing irregular.
The problem affects males and females from adolescents to older adults. It is most common in middle-aged women.