Changes in the lumbosacral angle, sacral inclination and the curvature of the lumbar spine during aging.

Measurements of the curvature of the lumbar spine are useful in the investigations of low back pain. It is unclear whether the degree of lumbar lordosis, sacral inclination and lumbosacral angulation are the same for all normal adults. Radiographic studies were carried out on the lumbar spines of subjects aged 9-61 years. Mean and 95% tolerance ranges of the values of lumbar lordosis, lumbosacral angle and sacral inclination for adult age groups up to the sixth decade are given. The results showed that all three parameters varied steadily with age. The pattern of changes differed in males and females. Females had greater angles than males. Sacral inclination appeared to be a more important determinant of the degree of lumbar lordosis. All three parameters showed a tendency to decrease after the sixth decade. The significance of the findings is discussed.