The pterosaur wing membrane is divided into three basic units.
The first, called the propatagium ("fore membrane"), was the forward-most part of the wing and attached between the wrist and shoulder, creating the "leading edge" during flight.
The brachiopatagium ("arm membrane") was the primary component of the wing, stretching from the highly elongated fourth finger of the hand to the hindlimbs.
Finally, at least some pterosaur groups had a membrane that stretched between the legs, possibly connecting to or incorporating the tail, called the uropatagium; the extent of this membrane is not certain, as studies on Sordes seem to suggest that it simply connected the legs but did not involve the tail (rendering it a cruropatagium).
A common interpretation is that non-pterodactyloid pterosaurs had a broader uro/cruropatagium stretched between their long fifth toes, with pterodactyloids, lacking such toes, only having membranes running along the legs.

There has been considerable argument among paleontologists about whether the main wing membranes (brachiopatagia) attached to the hindlimbs, and if so, where.
Fossils of the rhamphorhynchoid Sordes, the anurognathid Jeholopterus, and a pterodactyloid from the Santana Formation seem to demonstrate that the wing membrane did attach to the hindlimbs, at least in some species.
However, modern bats and flying squirrels show considerable variation in the extent of their wing membranes and it is possible that, like these groups, different species of pterosaur had different wing designs.
Indeed, analysis of pterosaur limb proportions shows that there was considerable variation, possibly reflecting a variety of wing-plans.

The bony elements of the arm formed a mechanism to support and extend the wing.
Near the body, the humerus or upper arm bone is short but powerfully built.
It sports a large deltopectoral crest, to which the major flight muscles are attached.
Despite the considerable forces exerted on it, the humerus is hollow or pneumatised inside, reinforced by bone struts.
The long bones of the lower arm, the ulna and radius, are much longer than the humerus.
They were probably incapable of pronation.

A bone unique to pterosaurs, known as the pteroid, connected to the wrist and helped to support the forward membrane (the propatagium) between the wrist and shoulder.
Evidence of webbing between the three free fingers of the pterosaur forelimb suggests that this forward membrane may have been more extensive than the simple pteroid-to-shoulder connection traditionally depicted in life restorations.
The position of the pteroid bone itself has been controversial.
Some scientists, notably Matthew Wilkinson, have argued that the pteroid pointed forward, extending the forward membrane and allowing it to function as an adjustable flap.
This view was contradicted in a 2007 paper by Chris Bennett, who showed that the pteroid did not articulate as previously thought and could not have pointed forward, but rather was directed inward toward the body as traditionally interpreted.
David Peters in 2009 proposed that the pteroid articulated with the 'saddle' of the radiale (proximal syncarpal) and both the pteroid and preaxial carpal were migrated centralia.
This seems to be confirmed by specimens of Changchengopterus pani and Darwinopterus linglongtaensis showing the pteroid in articulation with the proximal syncarpal.

The pterosaur wrist consists of two inner (proximal, at the side of the long bones of the arm) and four outer (distal, at the side of the hand) carpals (wrist bones), excluding the pteroid bone, which may itself be a modified distal carpal.
The proximal carpals are fused together into a "syncarpal" in mature specimens, while three of the distal carpals fuse to form a distal syncarpal.
The remaining distal carpal, referred to here as the medial carpal, but which has also been termed the distal lateral, or pre-axial carpal, articulates on a vertically elongate biconvex facet on the anterior surface of the distal syncarpal.
The medial carpal bears a deep concave fovea that opens anteriorly,
The pterosaur wing membrane is divided into three basic units. The first, called the propatagium ("fore membrane"), was the forward-most part of the wing and attached between the wrist and shoulder, creating the "leading edge" during flight. The brachiopatagium ("arm membrane") was the primary component of the wing, stretching from the highly elongated fourth finger of the hand to the hindlimbs. Finally, at least some pterosaur groups had a membrane that stretched between the legs, possibly connecting to or incorporating the tail, called the uropatagium; the extent of this membrane is not certain, as studies on Sordes seem to suggest that it simply connected the legs but did not involve the tail (rendering it a cruropatagium). A common interpretation is that non-pterodactyloid pterosaurs had a broader uro/cruropatagium stretched between their long fifth toes, with pterodactyloids, lacking such toes, only having membranes running along the legs.
There has been considerable argument among paleontologists about whether the main wing membranes (brachiopatagia) attached to the hindlimbs, and if so, where. Fossils of the rhamphorhynchoid Sordes, the anurognathid Jeholopterus, and a pterodactyloid from the Santana Formation seem to demonstrate that the wing membrane did attach to the hindlimbs, at least in some species. However, modern bats and flying squirrels show considerable variation in the extent of their wing membranes and it is possible that, like these groups, different species of pterosaur had different wing designs. Indeed, analysis of pterosaur limb proportions shows that there was considerable variation, possibly reflecting a variety of wing-plans.
The bony elements of the arm formed a mechanism to support and extend the wing. Near the body, the humerus or upper arm bone is short but powerfully built. It sports a large deltopectoral crest, to which the major flight muscles are attached. Despite the considerable forces exerted on it, the humerus is hollow or pneumatised inside, reinforced by bone struts. The long bones of the lower arm, the ulna and radius, are much longer than the humerus. They were probably incapable of pronation.
A bone unique to pterosaurs, known as the pteroid, connected to the wrist and helped to support the forward membrane (the propatagium) between the wrist and shoulder. Evidence of webbing between the three free fingers of the pterosaur forelimb suggests that this forward membrane may have been more extensive than the simple pteroid-to-shoulder connection traditionally depicted in life restorations. The position of the pteroid bone itself has been controversial. Some scientists, notably Matthew Wilkinson, have argued that the pteroid pointed forward, extending the forward membrane and allowing it to function as an adjustable flap. This view was contradicted in a 2007 paper by Chris Bennett, who showed that the pteroid did not articulate as previously thought and could not have pointed forward, but rather was directed inward toward the body as traditionally interpreted. David Peters in 2009 proposed that the pteroid articulated with the 'saddle' of the radiale (proximal syncarpal) and both the pteroid and preaxial carpal were migrated centralia. This seems to be confirmed by specimens of Changchengopterus pani and Darwinopterus linglongtaensis showing the pteroid in articulation with the proximal syncarpal.
The pterosaur wrist consists of two inner (proximal, at the side of the long bones of the arm) and four outer (distal, at the side of the hand) carpals (wrist bones), excluding the pteroid bone, which may itself be a modified distal carpal. The proximal carpals are fused together into a "syncarpal" in mature specimens, while three of the distal carpals fuse to form a distal syncarpal. The remaining distal carpal, referred to here as the medial carpal, but which has also been termed the distal lateral, or pre-axial carpal, articulates on a vertically elongate biconvex facet on the anterior surface of the distal syncarpal. The medial carpal bears a deep concave fovea that opens anteriorly,
Pterosaur