<unk>  is a congenital anomaly in tetrapods that involves duplication of elements of the foot on the hind limb. It comes from the Greek roots diplo = "double" and pod = "foot".<unk>  is often found in conjunction with other structural abnormalities and can be lethal. It is more extreme than polydactyly, the presence of extra digits.
Diplopodia
Axon hillock
Lines of Zahn
Cradle cap
Ossification center
Intramedullary rod
Epiphyseal plate
Cramp-ring