A lump can be found just behind the toe at the joint where the toe attaches to the foot. This is due to a prominence of the head of the metatarsal bone. This happens when there is an alignment problem with the bones in the ball of the foot. The area may or may not cause a problem. If the lump is behind the big toe joint, it is a sign of a progressive arthritis of the joint. The condition is called Hallux Limitus or degenerative arthritis. Treatment consists of orthotics to improve the function of the joint and/or surgical correction.