There are carpometacarpal (CM) joint, metacarpophalangeal (MCP) joint, proximal and distal interphalangeal joints in the hand. The bony structure includes carpals, metacarpals, and proximal, middle and distal phalanges bones. Each bone, except the carpals, is joined by tendons that flex or extend the joints on the dorsal and palmar surfaces. At the proximal levels, intrinsic muscles of the hand also produce motions to either side.