Sacrum
The sacrum is shaped like a quadrangular pyramid with the base facing upwards and the apex facing downwards. It articulates superiorly with the 5th Lumbar Vertebra and inferiorly with the Coccyx.
The sacrum is the fusion of five vertebrae and has 4 faces: two lateral, one anterior and one posterior.
Side Faces
The main accident of the lateral faces are the Auricular Faces that serve as a point of articulation with the hip bone ( Iliac ).
Anterior Face (Iliac)
It is concave and has four transverse ridges, which correspond to the intervertebral discs. It has four anterior sacral foramina.
Rear Face ( Dorsal )
It is convex and has the following bony features:
- Median Sacral Crest – has three or four spinous processes.
- Lateral Sacral Crest – formed by tubercles that represent the transverse processes of the sacral vertebrae.
- Intermediate Sacral Crest – tubercles produced by the fusion of articular processes.
- Posterior Sacral Foramina – lateral to the intermediate crest.
- Sacral Hiatus – wide opening formed by the separation of the laminae of the fifth sacral vertebra with the posterior midline.
- Sacral Horns – tubercles representing posterior articular processes of the fifth sacral vertebra.
Basis
- Promontory
- sacral wings
- Right and Left Superior Articular Processes – articulate with the fifth lumbar vertebra.
- Sacral Canal – vertebral canal of the sacrum.
Apex
It articulates with the coccyx.
| SACRED - BACK VIEW |
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| Source: NETTER, Frank H.. Atlas of Human Anatomy. 2nd edition Porto Alegre: Artmed, 2000. |
| SACRED - BACK VIEW |
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| Source: NETTER, Frank H.. Atlas of Human Anatomy. 2nd edition Porto Alegre: Artmed, 2000. |
| SACRO - SIDE VIEW |
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| Source: NETTER, Frank H.. Atlas of Human Anatomy. 2nd edition Porto Alegre: Artmed, 2000. |