A vertebra is one of 33 bony segments that form the spinal column of humans. There are 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused into one sacrum bone) and 4 coccygeal (fused into one coccyx bone).
VERTEBRA
Meaning of VERTEBRA in English
English dictionary of medicine. Английский словарь медицины. 2012