SACRALIZATION OF FIFTH LUMBAR VERTEBRA

Sacrum is a wedge shaped bone formed by the fusion of five sacral vertebrae with ossification of the intervertebral joints. Broadest superiorly, the sacrum articulates with the fifth lumbar vertebra, while inferiorly, it narrows to articulate with the coccyx forming four pairs of sacral foramina. But during the osteology demonstration class of undergraduate MBBS students a sacrum with five pairs of sacral foramina was detected. The sacrum may contain six vertebrae with five pairs of sacral foramina. It may be due to the development of an additional sacral element or fusion of fifth lumbar vertebra with first sacral vertebra or fusion of first coccygeal vertebra with fifth sacral vertebra. Sacralization of fifth lumbar vertebra has come into considerable prominence on account of fact that radiography has thrown its beam of light upon a condition about which very little was known.