Patagium
- Pronunciation
- /puh-TAY-jee-um/
- Category
- Anatomy
- Singular
- patagium
- Plural
- patagia
Definition
A membranous, often elastic skin fold that extends between body parts to form an aerodynamic surface, enabling gliding or powered by increasing surface area and generating lift. In vertebrates, the patagium typically stretches along the flank between forelimb and hindlimb (propatagium anteriorly, plagiopatagium centrally, uropatagium or interfemoral between hindlimbs), with muscle fibers and connective tissue providing structural support and control. The term derives from Greek *patageion* (small flap), and analogous structures have evolved convergently in bats, pterosaurs, birds (propatagium only), gliding squirrels (*Petaurista*), colugos (*Dermoptera*), flying lizards (*Draco*), and frogs (*Rhacophorus*). While achieve flight through wings rather than patagia, the term appears in comparative biomechanics and functional literature when discussing wing origin theories and convergent aerodynamic solutions.
Etymology
New Latin, from Greek patageion, diminutive of patage, clapper or flap
Example
In the Malayan colugo (*Galeopterus variegatus*), the patagium extends from the neck to the fingertips, along the flanks, and to the toes, creating a nearly continuous gliding surface that can span over 70 cm and supports controlled glides exceeding 100 meters between rainforest trees.
Synonyms
- flight membrane
- gliding membrane
- interfemoral membrane (specific to hindlimb portion)
- chiropatagium (bat-specific, rare)
Related Terms
- uropatagium
- propatagium
- plagiopatagium
- interfemoral membrane
- chiroptera
- dermoptera
- gliding
- flight membrane
- wing loading
- aerodynamic surface
Usage Notes
distinguish regional patagial zones: the propatagium (, from shoulder to wrist), plagiopatagium (main body surface), and uropatagium (between hindlimbs, also called interfemoral ). The term is occasionally misapplied to loose skin folds in non- mammals; precise usage requires demonstration of aerodynamic function. In paleontology, fossilized patagia are inferred from skeletal proportions and preserved soft tissue impressions. The homonymous trematode *Patagium* Heymann, 1905 (Auridistomidae) is taxonomically unrelated and rarely encountered in modern literature.