part of part of in taxon derived from ancestral fusion of derived from ancestral fusion of Archosauria carpal bone skeleton of manus metacarpal bone manus bone carpometacarpus Wikipedia:Carpometacarpus UBERON:0011205 carpometacarpus bone The carpometacarpus is the fusion of the carpal and metacarpal bone, essentially a single fused bone between the wrist and the knuckles. It is a smallish bone in most birds, generally flattened and with a large hole in the middle. In flightless birds, however, its shape may be slightly different, or it might be absent entirely.