part_of part of part of Homo sapiens anatomical system vertebral column dorsum skeletal system bone element postcranial axial skeleton trunk pelvic region of trunk fused sacrum http://upload.wikimedia.org/wikipedia/commons/e/ec/Gray95.png https://cdn.humanatlas.io/digital-objects/ref-organ/pelvis-female/v1.3/assets/3d-vh-f-pelvis.glb https://cdn.humanatlas.io/digital-objects/ref-organ/pelvis-male/v1.3/assets/3d-vh-m-pelvis.glb sacrum [sacral vertebrae I - V] SCTID:264186006 sacral bone the AAO class 'sacrum' is deliberately placed under 'sacral vertebra' rather than here 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 sacral MESH:D012447 os sacrum os sacrum [vertebrae sacrales I - V] UBERON:0003690 sacrum Wikipedia:Sacrum FMA:16202 sacrum [sacral vertebrae I-V]