Human hand. Artwork showing the bones of the index finger and thumb in a human hand. The long bones of the thumb are (left to right): metacarpal, proximal phalanx and distal phalanx. In the index finger, the metacarpal and proximal phalanx are in the same order, but there is a middle phalanx (here seen pointing downward) between the proximal and distal phalanx (tip).