During a compression fracture, a bone in the spine collapses. These tend to be more frequent in the middle part of the spine or in the upper portion of the lower spine region. A lower vertebra in the middle of the spine or the first vertebra in the lumbar region is most commonly affected.
Osteoporosis is the most common cause for compression fractures, as weak bones eventually collapse under increased exertion. However, falls or excessive pressure can result in compression fractures.