The Skeletal System at a Glance: No Bones About It

Okay, lets pull your skeleton out of the closet; I mean your body and learn a little bit more about the body's support system.

The skeleton is the supportive structure that helps you move, stand up-right and gives your body it's frame. It's made up of 206 bones and its functions include:

• Support of muscles, blood vessels, skin, fat and nerves. It also stabilizes them.
• It protects the vital internal organs of the body.
• It assists in movement by working in conjunction with muscles, tendons and ligaments.
• It stores mineral salts like calcium and phosphorous.
• It's the manufacturing plant for blood cells.

Did you know when a fetus is forming, the complete skeleton is formed by the third month in utero? It's mostly cartilage at this time as ossification hasn't started, but it's one of the first systems of the body to form.

Ossification is the formation of bones and this occurs during the last 6 months of pregnancy.

Cartilage, ligaments and tendons are also considered to be part of the skeletal system.
Cartilage is actually a connective tissue. It helps bones move smoothly against each other. Ligaments are also connective tissue but they are very tough. Their function is to connect one bone to another. Tendons are somewhat like ligaments except they connect muscles to bones.

Bones are classified based on their shape and are divided into five categories: Sesamoid, short, long, irregular and flat.

Sesamoid bones are round and small and encased within tendons. The kneecap is the largest sesamoid bone. Some ankle and wrist bones are also classified as sesamoid bones. The location of sesamoid bones are adjacent to joints.

Short bones are a bit irregular and lack a long axis. The consist of the carpal bones in the wrist and the tarsal bones in the foot. Short bones have a thin layer of tissue covering them.

Long bones are bones that their length exceed their width. They include the tibia, fibula, femar, ulna, radias and humerous bones, but also the metacarpals, metatarsals and the phalanges. These bones are unique because they are a bit thicker in the middle and have a slight curvature. This design is for weight distribution.

Irregular bones are odd shaped and include the ossicles and vertebrae. Irregular bones are spongy but they're enclosed in layers of compact bone.

Flat bones consist of the pelvic bone, some of the bones of the skull, the ribs, sternum, or wherever theres a need for extensive attachment or protection of inner organs.

Bones also contain functional markings which help one bone join with another. The projection markings are called processes and the depression markings are called fossae. Markings also provide an attachment surface for muscles.

The skeletal system is the basic foundation the rest of our body is built on. Without it we would be no more than a jellyfish. There's no way this brief introduction could cover all the information on bones and their structure, it is merely to give you a brief understanding of their types and functions.