Osteoporosis/trauma. The vertebrae are the building blocks of the spine. They are made of cancellous (spongy) bone. They are stacked one on top of another separated by the vertebral discs. A compression fracture occurs when the bone cannot support the load. Sometimes it is because the bone is weak (osteoporosis) and sometimes because of severe load (a fall or an auto accident). The bone is compressed or collapsed.
Vertebral compressio. Means that the shape of the vertebral body of one vertebra is different, instead of being square, it turns triangular. This is cause by osteoporosis and injuries to the area, it can be sudden or gradual.