The hand consists of the wrist bones (ossa carpi), the metacarpal bones (ossa metacarpi) and the finger bones (ossa digitorum manus). The wrist bones are arranged in two rows of four. The metacarpal bones are built in a similar way—on each bone we separate a proximal epiphysis (called the base), a shaft and a distal set (called the head). The shafts are narrow and slightly convex towards the back of the hand. The fingers 2–5 have three phalanges: the proximal (phalanx proximalis), the middle (phalanx media) and the distal (phalanx distalis). The thumb has only two phalanges: proximal and distal. The shafts of the phalanges are flattened on the palm side and slightly convex on the palm side. The next fingers are the thumb (pollex), index finger (index), middle finger (medius), ring finger (anularis), and little finger (minimus).