Function of the Skeleton
The skeleton has five major functions. These are:
- Support - the body is kept in position by the muscles that attach to the skeleton.
- Protection- the flat bones protect the internal organs.
- Movement - provided by the joints
- Production of Blood - blood cells are produced in the red bone marrow in the centre of some bones, including the pelvis, ribs, vertebrae and stenum. The yellow bone marrow stores fat. The yellow bone marrow can convert to red bone marrow if the body needs additional blood production.
- Storage - Minerals are stored in the bone, mostly calcium and phosphorus.
Note 1: The pelvic girdle, an irregular bone, is fused in adults. The three bones that fuse to make the pelvic girdle are the ilium, ischium and pubis (pubic bone). These three individual bones are flat bones.
Note 2: The talus is a bone in the ankle that forms a synovial joint with the tibia and fibula.
The Spinal Column
The spinal column is made up of 33 vertebrae, in a 7-12-5-5-4 combination, as can be seen from the diagram below. Note that the 5 vertebrae in the sacrum and the 4 vertebrae in the coccyx are fused. Note also that the spine is curved, and these curves act as shock absorbers.
The spine may become stressed if these curves are altered.
There are three main body types, known as somatotypes. These are:
- Endomorphs - Heavy build, wide hips, higher percentage of fat to muscle eg. Fern Brittain
- Mesomorphs - Athletic, more muscle, less fat, narrow hips eg.
- Ectomorphs - Skinny, small frame, narrow, flat chested, less muscle and fat eg.