The Appendicular Skeleton

The appendicular skeleton, totalling 126 bones, is made up of the bones of the limbs together with the girdles that attach each pair of limbs to the axial skeleton, and its principal function is to enable locomotion and the manipulation of objects.

The pectoral (shoulder) girdle, made of 4 bones (a clavicle, or collar bone, and a scapula, or shoulder blade, on each side), suspends the upper limb from the axial skeleton and provides a wide, shallow, highly mobile socket for the shoulder joint. Each upper limb is made of a single humerus in the upper arm, and a radius and an ulna, lying side by side, in the forearm; the wrist and hand contain 8 small carpal bones, 5 metacarpal bones forming the palm, and 14 phalanges forming the fingers and thumb. Counting both sides together, this gives 2 humeri + 2 radii + 2 ulnae + 16 carpals + 10 metacarpals + 28 phalanges, a total of 60 bones for the two upper limbs. …