In the Denis classification of spinal fractures, the middle column consists of:

• A The posterior longitudinal ligament, posterior annulus, and posterior wall of the vertebral body ✓
• B The anterior longitudinal ligament and anterior vertebral body
• C The pedicles, laminae, facet joints, and posterior ligamentous complex
• D The spinous process, supraspinous and interspinous ligaments

Explanation

Denis three-column concept: Anterior column — anterior longitudinal ligament (ALL), anterior half of the vertebral body and annulus; Middle column — posterior wall of the vertebral body, posterior half of the disc, and posterior longitudinal ligament (PLL); Posterior column — neural arch (pedicles, laminae, facets), supraspinous ligament, interspinous ligament, ligamentum flavum, and facet joint capsules. The middle column is critical — disruption of the middle column (burst fractures, flexion-distraction) indicates instability. Failure of ≥2 columns denotes an unstable fracture requiring surgical stabilisation.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.