Proximal rows somewhat join with radial and ulnar distal ends. From thumb to little finger, scaphoid and lunate bones articulate with radius' distal ends, while triquetrum and pisiform bones only line up with ulnas' distal ends. Pisiform bones lay against triquetrum bones that lay against hamate bones. Distal carpal rows articulate with proximal ends of five metacarpals. Wrist joint actions include metacarpal movements.
Metacarpals move anteriorly, posteriorly, medially and laterally.
Extensions occur when wrist joint muscles contract to move metacarpals' posterior surfaces closer to forearms' posterior surfaces. Flexions occur when wrist joint muscles contract to move metacarpals' anterior surfaces closer to forearms' anterior surfaces. Radial Flexions occur when wrist joint muscles contract to move thumbs closer to radius' lateral surfaces. Ulnar Flexions occur when wrist joint muscles contract to move little fingers closer to ulnas' medial surfaces. Wrist Joint Muscles Wrist joint muscles attach to metacarpals from humeruses.