Description
The appendicular skeleton is one of the two parts that form the skeletal system, the other part being the axial skeleton. The joints of the appendicular skeleton are generally more mobile, and therefore less stable, than those of the axial skeleton.
The bones of the appendicular skeleton form the skeletal framework of the appendages. For classification purposes, the bones of the appendicular skeleton can be arbitrarily divided into two distinct groups:
- bones of the upper limb;
- bones of the lower limb.
The bones of the upper and lower limbs are organized similarly and consist of the same basic structural elements, including a proximally located girdle (e.g., pectoral and pelvic girdles) and distally located phalanges. However, the bones of the upper and lower limbs are different in terms of their:
- morphology, where the bones of the upper limbs are primarily adapted to support prehensile activities (i.e., gripping), while the bones of the lower limb are primarily adapted for weight-bearing functions such as standing and locomotion;
- relationship with the axial skeleton, where the upper limb does not articulate with the vertebral column and has a relatively small point of articulation with the axial skeleton, whereas the lower limb does articulate with the vertebral column and has a much larger articulation site with the axial skeleton.
Related parts of the anatomy
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Appendicular Skeleton
The appendicular skeleton consists of the bones of the arms (or upper limbs) and legs (or lower limbs) as well as their supporting structures where they articulate with the axial skeleton.
