The defect in the pars interarticularisof spondyloisthesis may be dependent on contributing factors related to trauma and stress to which the neural arch is subjected, superimposed on a hereditary diasthesis. Posterior wedging of 5th lumber vertebral body in lumbosacral spondyloisthesis together with the degree of slip have been measured. The average wedging in sponlylolisthesis is significantly greater than patient without this condition, and forms a characteristic radiologial sign. The degree of wedging and slip show a statistically valid correlation. the diagnosis of sponlylolistheiss is becomming more prevalent as the complexity of our society result in the increasing use of roentgenography of the lumbar spine. Isolated lateral deviation and rotation of spinous process seen in anteroposterior raiograhhs of the lumbar spine seems to be associated with pathology in the pars interarticularis.