Skeletal System

The skeletal system refers to a person's bones. Bones are made of minerals like calcium, and they are rigid. Without bones, bodies would have no form and delicate internal organs would be exposed to damage. Bones are connected to one another by joints, which allow them to move in certain ways.

Your bones all join up to make a frame for your body called the skeleton. The smallest bone in your body is the same length as a grain of rice. It lies deep inside your ear. 

There are 206 bones in an adult skeleton. Over half of these bones are in your hands and feet, where the most complicated body movements are performed.

Did you know you have seven bones in your neck, the same number as a giraffe? The top one allows you to move your head up and down, the second lets you move your head from side to side.

Bone is a very hard material and one of the last parts to rot away when a body is buried. 

The most complex part of the skeleton is the skull. It is made of many bones that fit together tightly, to protect the brain. 

Your spine is a series of bones running down the back of your body. Your spine contains 24 separate bones called vertebrae. At the base of your spine is the coccyx, consisting of four fused vertebrae. 

The ribcage forms a cage around your heart and lungs. Rib bones are curved and are also thinner and more bendy than the bones in your spine.

The outer surface of a bone is hard and dry, but the inside is definitely alive. The inside of bone have a honeycomb structure with lots of spaces, making the bone weigh less than if it was solid. Marrow fills the centre of your larger bones. It supplies your body with red blood cells at a rate of 3 million cells per second. The hardest part of the bone is the outer layer, made of calcium. Teeth are also made from calcium. 


Further Reading