Bones of Upper Limb (Left)

Description

The bones of the upper limb (superior appendicular skeleton) provide the skeletal framework for both the gross and fine motor functions of the upper limb. For classification purposes, the bones of the upper limb can be arbitrarily divided into two distinct groups based on their anatomical relationship with the axial skeleton:

- the bones of the pectoral girdle, which articulate directly with the axial skeleton and are therefore less mobile;

- the bones of the free part of upper limb, which don’t articulate directly with the axial skeleton and are therefore more mobile.

The majority of the bones in the upper limb are long bones (e.g., humerus, radius, and ulna) that, from proximal to distal, increase in number but decrease in size. The upper limb also consists of flat, short, and sesamoid bones (e.g., scapula, scaphoid, and pisiform bones, respectively).

The joints of the upper limb demonstrate greater mobility than their lower limb counterparts; however, as a result, they’re less stable. The most proximal joints of the upper limb exhibit the greatest range of motion but become gradually more restricted distally.