Denis classification of spinal fractures

Denis divided the spine into three columns - anterior, middle and posterior. If two or more of these columns are damaged then the spine is unstable.

• the anterior column comprises the anterior longitudunal ligament and the anterior half of the vertebral body.
  
  
• the middle column comprises the posterior half of the vertebral body and the posterior longitudunal ligament.
  
  
• the posterior column comprises the pedicles, the facet joints and the supraspinous ligaments.

In adition to proposing the 'three column spine' Denis also defined four types of spinal fractures;

• wedge fracture - stable
• burst fracture - stable
• seat belt fracture (and 'Chance fracture') - unstable
• fracture dislocation - unstable