Denis' three column concept helps to determine whether a vertebral<unk> is stable or<unk> 
I: Anterior column
Anterior longitudinal ligament
Anterior 1/2 of the vertebral body and disk
II: Middle column
Posterior 1/2 of the vertebral body and disk
Posterior longitudinal ligament
III: Posterior column
Facet joints
Ligament flavum
Posterior elements
Anterior longitudinal ligament
Anterior 1/2 of the vertebral body and disk
Posterior 1/2 of the vertebral body and disk
Posterior longitudinal ligament
Facet joints
Ligament flavum
Posterior elements
Jefferson's<unk> Bilateral Cervical facet dislocation
Odontoid<unk>  type II or III
Atlanto-occipital dissociation
Hangman's<unk> Flexion teardrop
Mnemonic: "Jefferson Bit Off A Hangman's Thumb"
Unstable spine fractures
Cervical fractures and dislocations
Cervical burst fracture
Vertebral fractures and dislocations
Thoracic and lumbar compression fractures
Thoracic burst fracture
Cervical disk herniation
Spinal stenosis