While humans usually walk with the soles of their feet on the ground, i.e. plantigrade locomotion, digitigrade animals walk on their distal and intermediate phalanges. Digitigrade locomotion is responsible for the distinctive hooked shape of dog legs.
There are anatomical differences between a plantigrade and digitigrade limb. Digitigrade animals have relatively long carpals and tarsals, and the bones which would correspond to the human ankle are thus set much higher in the limb than in a human. This effectively lengthens the foot, so much so that a digitigrade animal's "hands" and "feet" are often thought to correspond only to what would be the bones of the human toe or finger.