Patagium

• In bats, the skin forming the surface of the wing. It is an extension of the skin of the abdomen that runs to the tip of each digit, uniting the forelimb with the body.

• The patagium of a bat has four distinct parts:
  1. Propatagium: the patagium present from the neck to the first digit.
  2. Dactylopatagium: the portion found within the digits.
  3. Plagiopatagium: the portion found between the last digit and the hindlimbs.
  4. Uropatagium: the anterior portion of the body between the two hindlimbs.

• In the extinct flying pterosaurs, also the skin forming the surface of the wing. In these creatures the skin was extended to the tip of the very long fourth finger of each hand.

• The patagium of a pterosaur had three distinct parts:
  1. Propatagium: the patagium present from the shoulder to the wrist.
  2. Brachiopatagium: the portion stretching from the fourth finger to the hindlimbs.
  3. Uropatagium or cruropatagium: the anterior portion between the two hindlimbs, depending on whether it did or did not include the tail.

• In gliding species, such as some lizards, rodents and other mammals, the flat parachute-like extension of skin that catches the air, allowing them to glide.

• In some lepidopterans, one of a pair of small sensory organs situated at the bases of the anterior wings.

• In birds, the fold of skin extending from the humerus to the carpal joint, making up the leading edge of the wing.