Human upper limbs have several bones. An example is the clavicle which, joined to the more posterior scapula (another example), connects these limbs to the skeleton. Both are in pairs, are mobile and provide attachment for the muscles.
The humerus is the largest bone in the upper limb. It has a smooth and spherical head and its length (diaphysis) is smooth and thin. At one of its extremities, it participates in the elbow joint, connecting, in this region, to the ulna.
The ulna is the longest bone in the forearm. This is also articulated with the radio . Both attach to the wrist bones (carpal bones).
The hand divides into the carpus , metacarpal and phalanx . The carpal bones are eight , and they are distributed in two rows. In the proximal row, we have the scaphoid, lunate, pyramidal and pisiform bones. In the distal, the trapezius, trapezoid, capitate and hamate bones.
Following the carpal bones, follow the metacarpals . In these we have five long bones, numbered I to V starting from the thumb: these constitute the fingers of the hand. The head of these bones, distal end, articulates with their respective phalanges.
Each hand has 14 phalanges , and there are two on the thumb: proximal (first phalanx) and distal (second phalanx). The second to fourth fingers have three phalanges each: proximal, middle (second phalanx) and distal.
The proximal phalanges are longer than the distal ones, with those of the thumb being shorter and wider than those of the other fingers.