The sacrum is formed from the fusion of five sacral vertebrae, whose lines of fusion are indicated by the transverse ridges. The fused spinous processes form the median sacral crest, while the lateral sacral crest arises from the fused transverse processes. The coccyx is formed by the fusion of four small coccygeal vertebrae.
Cut Rita Zahara
“Sacrum and Coccyx,” Open Educational Resource (OER) - UNM, accessed July 31, 2021, http://oer.unm.ac.id/items/show/1073.