The Skeletal System
The skeleton is the name given to the collection of bones that holds the rest of our body up. Our
skeleton is very important because it provides the framework and support needed to perform the
various movements that occur during exercise or sport. This system has four major functions. It
protects our vital organs such as the brain, the heart and the lungs. It gives us the shape that we
have; without our skeleton, we would be a blob of blood and tissue on the floor. Our skeleton
allows us to move because our muscles are attached to our bones, so when our muscles move,
the bones move, and we move.
At birth, the skeleton has approximately 350 bones. By adulthood, due to fusions and joining of
bones, there will be 206 bones. More than half of your 206 bones are found in your hands and
feet. Bone is one of the hardest structures in the human body; it possesses a certain degree of
toughness and elasticity. The bone, itself can bend or stretch at very small degrees to allow certain
stresses to be placed upon it before reaching the extreme – fracture. Our bones don’t simply work
alone – they join together to form joints.
A tough, smooth shiny substance called cartilage covers the end of each bone. The cartilage-
coated bone-ends are kept apart by a thin film of slippery fluid that works like oil in a car. All of this
is so your bones won’t scratch and bump against each other when you move. Ligaments, which are
strong stretchy bands, hold our bones together. Contractile tissue moves the bones and creates
the necessary force and power of the athlete. This adult bone structure can be divided into two
systems, the axial skeleton (the trunk or center of our body) and the appendicular skeleton (our
limbs or extremities).
Skeleton Function
- Holds and protects organs
- Moveable rigid structure
- Red blood cells are manufactured in long bones
- Provides attachment for muscles
- Leverage system
Bones in the Skeleton
Skeletal bones are divided up into classes: long bones (which make up the limbs); short
bones (which are grouped together to strengthen and provide support for our skeleton); flat bones
(which protect our body); and irregular bones (odd shaped bones that don’t fit the other categories).
These can be seen schematically in Figure 1.
Long Bones are found in the extremities, and each consists of a body, or diaphysis, which
is cylindrical. It has a central cavity and a wall consisting of dense, compact bone. The cavity in
the middle of the body, or medullary cavity, contains cancellous bone, which looks like a sponge.
It has very porous areas that allow for the blood to pass through and bone marrow to be formed.
The ends of the long bone are for articulation and to create surfaces for muscular attachment. They
are termed epiphyses, and consist of cancellous or porous tissue surrounded by thin compact