A compression fracture occurs when a bone breaks because it's not strong enough to support the weight it usually carries. Rather than snapping or shattering, the bone flattens and compresses. Vertebral compression fractures are the most common type.
Vertebral compression fractures are sometimes due to traumatic injuries like falls or auto accidents. Tumors in or on your spine can also make the bone so weak it collapses. The leading cause of vertebral compression fractures, however, is osteoporosis.
Osteoporosis is a condition where your bones lose their density, making them weak and brittle. If you have advanced osteoporosis, your bones can fracture easily, even when you're doing everyday activities, and vertebrae are especially vulnerable.