Figure 16. A in Three-dimensional geometry of a pterosaur wing skeleton, and its implications for aerial and terrestrial locomotion

Figure 16. A, reconstructed articular surfaces of the right knuckle joint of Coloborhynchus robustus. Elements are oriented as in Figure 7: wing metacarpal in lateral view and wing-finger phalanx 1 in medial view. Scale bar: 50 mm. B, diagrammatic representation of (A), showing contact areas in the close-packed position and the joint axis. C, right wing metacarpal and wing-finger phalanx 1 in the close-packed position in dorsal aspect, viewed along the joint axis. D, Right wing metacarpal and wing-finger phalanx 1 at maximum flexion in dorsal aspect, viewed along the joint axis, which remains fixed with respect to the wing metacarpal throughout flexion. E, cross section X–X′ of the wing metacarpal viewed medially, with the proximal end of wing-finger phalanx 1 behind, and with the knuckle joint at maximum extension. F, Cross section X–X′ of the wing metacarpal viewed medially, with the proximal end of wing-finger phalanx 1 viewed from behind, with the knuckle joint at maximum flexion. The broken line indicates the position that wing-finger phalanx 1 would take if no conjunct rotation took place during flexion: this position is impossible, as the posterior part of the articular head of wing-finger phalanx 1 would overlap the shaft of the wing metacarpal. For a list of anatomical/ arthrological abbreviations, see Appendix 1.