Three column concept of the spine
This is a concept that was initially devised by Dr. Francis Denis to describe thoracolumbar spinal injuries. The anterior column of the spine is formed by the anterior longitudinal ligament, anterior annulus fibrosus, and anterior half of the vertebral bodies. The middle column of the spine is formed by the posterior longitudinal ligament, posterior annulus fibrosus, and posterior half of the vertebral bodies. The posterior column of the spine is formed by the posterior arch and interconnecting ligaments. Generally, if two or more spinal columns are involved in an injury, then the spine is considered to be unstable.