A 60-year-old woman with long-standing ankylosing spondylitis presents with a severe fixed kyphotic deformity of the thoracic spine, unable to look straight ahead. Which vertebral deformity is most characteristically responsible for this stooped posture in ankylosing spondylitis?

• A Anterior wedge fracture of multiple vertebral bodies
• B Collapse of intervertebral discs at multiple levels
• C Bamboo spine with syndesmophyte formation and squaring of vertebral bodies ✓
• D Compression fracture of the thoracolumbar junction (T12-L1)

Explanation

Ankylosing spondylitis causes ossification of the outer fibers of the annulus fibrosus, forming syndesmophytes that bridge adjacent vertebrae, giving a bamboo spine on imaging. Vertebral bodies become squared due to erosions at the corners (Romanus lesion). The fixed kyphosis results from ossification of spinal ligaments and facet joint fusion. Anterior wedge fractures are typical of osteoporosis, not the primary deformity of ankylosing spondylitis.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.