Sacralization is defined as addition of sacral elements by the fusion of fifth lumbar vertebra or first coccygeal vertebrae or both. The incorporation of the fifth lumbar vertebra with the sacrum may be unilateral or bilateral, producing partial or complete sacralization. Complete sacralization consists of complete bony union of abnormal transverse processes of fifth lumbar vertebra and sacrum. Incomplete sacralization shows a well-defined joint line between the transverse process and sacrum. Sacralization of the fifth lumbar vertebra has come into considerable prominence on account of the fact that radiography has thrown its beam of light upon a condition about which previously very little was known and which most certainly undiagnosable without an X-ray examination. During routine study of bones few sacral bones were observed with six bodies and five sacral foramina
