The hand is a structure of great importance for the body, since it is the tool we have to carry out endless activities.
The hand is made up of various structures. From the musculoskeletal point of view, it is made up of a group of muscles distributed in such a way that they allow all their ranges of movement, these include both the fingers and the region of the palm and wrist.
These muscles must be leveraged on a group of bones, which reach a total of 27 distributed between the wrist and the hand.
Carpal bones
The carpus is the part of the hand that corresponds to the wrist. There are eight bones distributed in two rows.
The upper row, which articulates with the bones of the forearm (ulna and radius) consists of 4 bones:
Scaphoid. It is the largest bone in this row, it is located on the side of the thumb and articulates with the radius bone. This bone is frequently fractured in trauma to the hand.
Semilunar. It is located on the internal side of the scaphoid, it receives this name because of its crescent shape.
Pyramidal. Located next to the lunate, shaped like a pyramid. Articulates with the ulna bone.
Pisiform. It is a small, rounded bone, located behind the pyramidal. It can be felt as a prominence on the back of the wrist, on the side of the little finger.
The lower row articulates with the metacarpal bones, it consists of four bones:
Trapeze. It is a cube-shaped bone that is located between the scaphoid and the second metacarpal, which corresponds to the index finger.
Trapezoid. It is a small bone that is located next to the trapezius bone.
Big bone. It is located inside the trapezoid. It is the largest bone in the carpus, which helps give it its forward concave vault shape.
Hook bone. It is the innermost bone of the second row of carpal bones. It receives this name since it has a hook-shaped prominence that is located aligned with the prominence of the pisiform bone located above.
Metacarpal bones
This structure It is made up of five bones, called metacarpals. Unlike the carpal bones, the metacarpals are elongated in shape, with a small bulge at both ends.
There are a total of five metacarpals. These are the first metacarpal, which corresponds to the thumb, the second metacarpal for the index, third metacarpal for the middle finger, fourth metacarpal for the ring finger, and fifth metacarpal for the little finger.
Finger bones
The fingers are made up of bones called phalanges. Each finger consists of three phalanges, except for the thumb, which only has two. These are named as follows:
Proximal phalanx: corresponds to the superior phalanx, it articulates with the corresponding metacarpal bone.
Middle phalanx: It is located in the middle part of the index, middle, ring and little fingers, the thumb does not have a middle phalanx.
Distal phalanx: located at the end of the finger, it articulates with the middle phalanx above.
Bones of the hand
Thus we see how the 27 bones that make up the hand and wrist are integrated: 8 metacarpal bones, 5 metacarpals and 14 phalanges.
Photos: Fotolia - 7activestudio / maya2008
