Your body contains 206 bones of various shapes and sizes. Bones protect your internal organs and support your body as you stand, sit, walk, and run.
A break in a bone is known as a fracture. In a greenstick fracture, the bone does not break all of the way through. Fractures are called simple, or closed, when the bone breaks but the skin does not. A compound, or open, fracture occurs when the broken bone tears through the skin.
The human spine is a flexible chain of 33 bones. The spine’s S-shaped curve supports the weight of the head, keeping it in an upright position.
Osteoporosis is a bone disease that occurs in older people. In this disease, bones gradually become so thin and weak that they break easily. These magnified pictures show a healthy bone, left, which has a normal spongy appearance, and a bone showing signs of osteoporosis, right.