Reliability of a noninvasive method for measuring the lumbar curve*

The purposes of this paper were to describe a clinically useful and noninvasive method of characterizing the shape of the lumbar spine and to evaluate the reliability and validity of this measurement technique. A flexible ruler was applied to the skin over the lumbar spines of 23 normal adults and an angle in degrees between two spinous processes (L 1 -S2) was calculated. lntratester test-retest reliability was good (ICC = 0.97, N = 89) for two separate measures of two spinal postures. The validity of the flexible ruler measurements was also good when compared to two different measurement techniques from a limited number of patient roentgenographs. The flexible ruler was determined to be a reliable and valid measurement technique for the shape of the lumbar spine and may prove helpful in quantifying lumbar postures and the effectiveness of clinical treatments designed to affect lumbar postures. J Orthop Sports Phys Ther 1986;8(4):180-184.