Carpal Joint

The carpal joint corresponds to the wrist of the tetrapod forelimb and is the pivot point where the wing folds against the body at rest. Wing chord — the standard measure of wing length in bird banding — is taken from the carpal joint to the tip of the longest primary. In many species, a distinct carpal bar (dark marking across the carpal area) forms a key field mark visible in flying birds, particularly in gulls and raptors.