We performed a prospective roentgenograph^ study to determine the incidence of Spondylolysis on 330 unselected medical students. The lumbar spines of 330 skeletons of medical students of both sexes were examined to determine the incidence of defects in pars interarticularis. The overall incidence of lumbar spina was 11.3 per cent of this group was together spondylolysis.
Keywords: Spondylolysis, Incidence, Spondylolisthesis, Lumbar 'nation, Sacralization, Spina Bifida.