The Patagium is the skin that forms the surface of the wings of bats. It is an extension of the skin of the abdomen and it unites the forelimbs with the body.
The patagium of bats has four distinctions:
Propatagium - the area from the neck to the first digit.
Dactylopatagium - the area within the digits.
Plagiopatagium - the area between the last digit and the hindlimbs.
Uropatagium - the area between the two hindlimbs.
The term also relates to the parachute-like skin flaps of flying lemurs and other gliding animals.