Hammer toes are caused by a biomechanical imbalance where the muscle structures of the toes are partially or completely dislocated. This causes the toes to become bent and crooked, and the joints of the toes to protrude. 

This condition can be hereditary or caused by inappropriate, ill-fitting shoes. Caution must be taken with hammertoes as they can lead to the development of ulcers and infections, which can be very serious for people with diabetics especially.

Hammertoes can be very painful, especially if irritated by a tight fitting shoe and can often lead to corns, calluses and sufferers can sometimes experience cramps in the toes and feet.