Question

Block vertebrae are seen in which of the following conditions?

• A. Paget's disease
• B. Leukemia
• C. Tuberculosis
• D. Klippel-Feil syndrome

Hint:

Think of the syndrome with a short neck and congenitally fused cervical vertebrae.

Answer 1

The Correct Option is D

Step 1: A block vertebra is a congenital vertebral anomaly in which two or more adjacent vertebral bodies fail to separate during development, so they remain fused into a single bony segment.

Step 2: Fusion of multiple cervical vertebral bodies is the hallmark of Klippel-Feil syndrome. This classically presents with the triad of a short neck, a low posterior hairline, and restricted neck movement, making it the correct answer.

Step 3: Block vertebrae are frequently associated with hemivertebrae, an absent vertebra above or below the block level, posterior element fusion, and the VACTERL group of anomalies.

Step 4: The distractors do not produce true congenital block vertebrae. Tuberculosis (Pott's spine) destroys disc spaces and can cause acquired bony ankylosis but is not a developmental block vertebra. Paget's disease causes cortical thickening and a picture-frame vertebra, and leukemia produces marrow infiltration changes, not fusion.