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Sacrum

Triangular-shaped bone at the bottom of the spine

In humans, the sacrum is a large, triangular bone. It is at the bottom of the spine and the upper and back part of the pelvis.

Sacrum
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Sacrum, pelvic surface
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Image of a male pelvis (sacrum is in center)
Details
Identifiers
LatinOs sacrum
MeSHD012447
TAA02.2.05.001
FMA16202
Anatomical terms of bone

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 concave facing forward, and tilted forward. The sacrum connects with four bones: