Compression fractures of the back are broken vertebrae, which are the bones of the spine.

In a compression fracture of the vertebra, the vertebral bone collapses. More than one vertebra may be affected. This condition may be caused by:

• Osteoporosis (the most common cause), which is caused by weakening of the bone due to the loss of calcium and other factors.
• Trauma to the back
• Tumors that started in the bone or spread to the bone from elsewhere

When the fracture occurs as a result of osteoporosis, the vertebrae in the chest (thoracic) or the lower back are usually affected. During the early stages, a break in the bone can get worse without any symptoms. Pain or other symptoms may be worse with walking, and are often not present when resting.

Multiple fractures may lead to kyphosis, a hump-like curvature of the spine (like the Hunchback of Notre Dame).