Dennis stability concept is based on which of the following?

Ans. b. 3 columns (Ref: Rockwood and Green's Fracture in Adults 7/e p1384)Dennis stability concept is based on 3 columns: Anterior, Middle and Posterior."One of the earliest mechanistic classification scheme for thoracolumbar fracture was given by Dennis, who attempted to elucidate the concept of spinal stability by assigning osseous and soft tissue structures into one of three columns (Anterior, Middle and Posterior)."- Rockwood and Green's Fracture in Adults 7/e p1384Dennis Stability ConceptOne of the earliest mechanistic classification scheme for thoracolumbar fracture was given by Dennis, who attempted to elucidate the concept of spinal stability by assigning osseous and soft tissue structures into one of three columnsQ:AnteriorMiddlePosterior* Anterior half of the vertebral body and anterior longitudinal ligament* Posterior half of the vertebral body /disc and posterior longitudinal ligament* Posterior elements including pedicles and facet joints and the remaining ligamentsThis system divides thoracolumbar injuries into 4 principal categories:CompressionBurstChanceFracture-dislocationWith this paradigm, the greatest emphasis is placed on the middle column, such that any injuries extending into this portion of the spine is generally assumed to be unstable.