Origin of the median and lateral sacral crests
The dorsal surface of the sacrum has three types of five rows of longitudinal crests.
- The median sacral crest is a bony fusion of the spinous processes and the interspinous ligaments of the five sacral vertebrae.
- Both lateral sides of the median sacral crest are weak intermediate sacral crests. These are fused articular processes.
- In addition, both lateral sides to the intermediate sacral crests are the lateral sacral crests. These are caused by the fusion of the transverse processes.