<prompt> Block vertebrae are seen in -Pagets diseaseLeukemiaTBKlippel - Feil syndrome  <response>: Ans. is d i.e., Klippel - Feil syndrome o A block vertebra is a type of vertebral anomaly where there is a failure of separation of two or more adjacent vertebral bodieso Associations1. There is a frequent association with hemivertebrae absent vertebra above or below block level, posterior element fusion2. Fusion of multiple cervical vertebral bodies is also seen in Klippel-Feil syndrome and VACTREL anamoly. 