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In terrestrialanimals,plantigrade locomotion meanswalking with the toes andmetatarsals flat on the ground. It is one of three forms of locomotion adopted by terrestrialmammals. The other options aredigitigrade, walking on thetoes and fingers with theheel andwrist permanently raised, andunguligrade, walking on thenail or nails of the toes (thehoof) with the heel/wrist and thedigits permanently raised. The leg of a plantigrade mammal includes the bones of the upper leg (femur/humerus) and lower leg (tibia andfibula/radius andulna). The leg of a digitigrade mammal also includes themetatarsals/metacarpals, the bones that in a human compose the arch of the foot and the palm of the hand. The leg of an unguligrade mammal also includes thephalanges, the finger and toe bones.
Among extinct animals, most early mammals such aspantodonts were plantigrade. A plantigrade foot is the primitive condition for mammals;digitigrade andunguligrade locomotion evolved later. Among archosaurs, thepterosaurs were partially plantigrade and walked on the whole of the hind foot and the fingers of the hand-wing.[1] Out of the plantigrade animals, only a few, such as humans, kangaroos and certain rodents, are obligatebipeds, while most others are functional bipeds.
Plantigradeanimals species include (but are not limited to):
The primary advantages of a plantigrade foot are stability and weight-bearing ability; plantigrade feet have the largest surface area. The primary disadvantage of a plantigrade foot is speed. With more bones and joints in the foot, the leg is both shorter and heavier at the far end, which makes it difficult to move rapidly.
In humans and other great apes, another possible advantage of a plantigrade foot is that it may enhance fighting performance by providing a more powerful stance for striking and grappling.[2]
Plantigrade foot occurs normally in humans in static postures ofstanding andsitting. It should also occur normally ingait (walking).Hypertonicity,spasticity,clonus, limited range of motion, abnormal flexion neural pattern, and a plantar flexor (calf) muscle contracture, as well as some forms offootwear such ashigh heeled shoes may contribute to an individual only standing and/or walking on their toes. It would be evident by the observable heel rise.