sacrum
/ˈseɪkrəm
/ /ˈsakrəm/noun (plural sacra /ˈseɪkrə/ /ˈsakrə/ or sacrums) Anatomy
A triangular bone in the lower back formed from fused vertebrae and situated between the two hip bones of the pelvis.The spinal column is composed of seven cervical vertebrae, twelve thoracic vertebrae, five lumbar vertebrae, the bony sacrum, and the coccyx....
- The lowest lumbar vertebra articulates with the sacrum, and this in turn with the coccyx.
- Vesalius said that the human sacrum normally has five vertebrae but one of six is by no means rare.
Origin
Mid 18th century: from Latin os sacrum, translation of Greek hieron osteon 'sacred bone' (from the belief that the soul resides in it).