Spinal Fractures: The Three-Column Concept

The Three-Column Concept
When describing and diagnosing spinal fractures, spine surgeons divide the spinal column into 3 sections:

1. Anterior column - made up of the anterior longitudinal ligament and the anterior one-half of the vertebral body, disc, and annulus.

2. Middle column - made up of the posterior one-half of the vertebral body, disc, and annulus, and the posterior longitudinal ligament.

3. Posterior column - made up of the facet joints, ligamentum flavum, the posterior elements and the interconnecting ligaments.

Types of Fractures
Most spinal fractures can be classified into 4 main types, including:

Wedge fractures - a compression fracture in which the front part of the vertebral body is crushed, forming a wedge shape.

Burst fractures - when the vertebral body is crushed in all directions, potentially causing bone fragments to enter the spinal canal.

Dislocation injuries - occurs when any part of the spinal column breaks away from another part, often caused by severe compression, rotation, or tension.

Seat belt fractures - often the result of a car crash when the passenger is wearing a lap-only seat belt and experiences a forceful forward flexion of the spine.

Stable and Unstable Fractures
Generally, a fracture is considered stable if only the anterior column is involved, as in the case of most wedge fractures. When the anterior and middle columns are involved, the fracture may be considered more unstable. When all three columns are involved, the fracture is by definition considered unstable, because of the loss of the integrity of the posterior stabilizing ligaments. The table below shows the types of fractures, the part or parts of the spine involved, and whether or not it is a stable or unstable injury.