A neuroma is a condition in which the outer layer of a foot nerve, usually one found in between the long bones of the foot along the bottom, becomes inflamed and swollen due to mechanical irritation from pressure under the foot. It is often called a pinched nerve, but this is a somewhat inaccurate description of the actual process. As the nerve is mechanically irritated by excessive pressure from below (the ground) as seen in cases of flat feet and high arches, and pressure from above (a ligament binding two adjacent long bones together), a reaction develops in the outer layer of the tissue covering the nerve. This leads to thickening, scar formation, and the eventual irritation of the underlying nerve fibers. As a result, pain develops in the ball of the foot that can feel hot, numbing, tingling, or simply like a lump, and often involves the two toes the specific nerve supplies sensation to.