Corns and Calluses
Corns and calluses are areas of thickened skin on the plantar surfaces of the foot or the tops of the toes. (dorsum of inter-phalangeal joints)
Corns and calluses develop from excess friction on the foot. Corns normally develop on the upper joints of the toes, while calluses generally develop on the underside of the foot.
Corns and calluses commonly develop when excess pronation disrupts the normal metatarsal bone relationship in the foot, which causes the toes to claw. Friction related to footwear is also a major contributor.