THE SKELETAL SYSTEM

Can you touch your backbone, your ankle bone, and your knee?

These are bones that are all part of your skeleton.

Just as a house could not stand without its wooden frame, your body cannot stand without its skeletal system.

Your skeleton also protects organs inside your body, such as your brain, heart, and lungs.

Your skeletal system also helps you move.

Muscles that move your body are attached to your skeleton.

BUILDING STRONG BONES

Your skeletal system needs certain minerals to help it stay healthy.

Minerals, such as calcium, help build bone tissue and keep bones strong.

One bone attaches to another bone at a joint.

Joints can be classified by the type of movement they allow.

Tissues around joints protect them. The tissues also help hold the bones together at the joint.

Ball-and-socket joints allow the most movement of any type of joint. Your shoulder and your hip have ball-and-socket joints.The end of one bone (ball) fits into a bowl-shaped area (socket) in another bone. These joints allow your bones to have CIRCULAR MOVEMENT.

A hinge joint lets your bones move backward and forward, the way a door moves. You can bend or straighten your leg because of the hinge joint at your knee.

THE HUMAN SKELETON

The adult human skeleton has 206 bones.

Some of the biggest bones are labeled in the following picture:

(pelvis)

(cranium)

Bone with enough calcium

Bone with lack of calcium

CALCIUM-RICH FOODS