What is Sacrum?
{{Infobox Bone | Name = Sacrum | Latin = Os sacrum | Image = Gray95.png | Caption = Sacrum, pelvic surface | Image2 = Gray241.png | Caption2 = Image of a male [[pelvis]] (sacrum is in center) | Articulations = |}} In humans, the '''sacrum''' is a large, triangular [[bone]]. It is at the bottom of the [[vertebral column|spine]] and the upper and back part of the [[pelvis]]. It fits like a wedge between the two [[hip]] bones. Its upper part connects with the last [[lumbar]] [[vertebra]], and bottom part with the [[coccyx]] (tailbone). During the first half of life these bones gradually fuse together. The sacrum is [[wikt:concave|concave]] facing forward, and tilted forward. The sacrum connects with four bones: * the last [[lumbar vertebra]] above * the [[coccyx|coccyx (tailbone)]] below * the [[Ilium (bone)|illium]] portion of the hip bone on either side [[Category:Bones]] [[Category:Back (anatomy)]]