part of derived from ancestral fusion of sacral vertebra bony pelvis fused sacrum sacrum [sacral vertebrae I - V] SCTID:264186006 sacral bone CALOHA:TS-2201 A collection of sacral vertebrae in the sacral region that are fused and part of the bony pelvis. GAID:241 EFO:0003071 NCIT:C33508 galen:Sacrum MESH:D012447 os sacrum os sacrum [vertebrae sacrales I - V] sacrum Wikipedia:Sacrum FMA:16202 sacrum [sacral vertebrae I-V] abdominal segment bone bone of dorsum pelvic region element sacral region of vertebral column irregular bone