And what about the thigh bone (femur) of the pterosaur?
"The normal articulation of the [pterosaur] femur resulted in a horizontal position of the femur shaft, probably during flight. For constructional reasons the femur could not be brought down to a vertical position."
"Putting the femur in its proper place and allowing some space for cartilage in the acetabulum, the most comfortable setting for the head would result in a horizontal position of the shaft".
"Pterosaur's hip sockets are oriented facing slightly upwards, and the head of the femur (thigh bone) is only moderately inward facing, suggesting that pterosaurs had a semi-erect stance. It would have been possible to lift the thigh into a horizontal position during flight as gliding lizards do."