Spondylolysis: its nature and anthropological significance

Abstract

Spondylolysis of the lower back is a kind of vertebral fracture that is unique to humans being related to anatomical features such as the lumbar curve which facilitate upright posture and bipedal locomotion in this species. It is virtually never seen in children before the age of walking and has not been observed in adults who were never able to walk. Although apparently produced on occasion by acute trauma, spondylolysis usually develops as a fatigue fracture in response to sustained or repeated stress. The occurrence of spondylolysis varies greatly from population to population with the highest frequencies, approaching 50%, seen in northern Alaskan and Greenlandic Eskimos. Males are affected more frequently than females, and the condition is common in athletes, particularly gymnasts, divers, polevaulters, and American football players. It is also seen among heavy laborers, especially if the job requires lifting. Although generally approached as a pathological condition requiring corrective treatment, spondylolysis, as well as the anterior slippage (olisthesis) that frequently accompanies it, usually produces relatively mild symptoms if any at all. In fact, it many even provide advantages such as greater flexibility in the lower back.