A comparison of actual and apparent lumbar lordosis in black and white adult females.

The purposes of this study were to investigate differences in lumbar lordosis in black and white adult females and to explain the clinical impression that blacks have a greater lordosis than whites. An actual lumbosacral lordosis angle (ALS) was measured from a standing right lateral lumbosacral radiograph using the angle formed from the intersection of lines drawn across the top of the second lumbar vertebral body (L2) and across the top of the sacrum. An actual lumbo-lumbar angle (ALL) was measured in the same manner, except the second line was drawn across the bottom of the fifth vertebral body (L5). To determine whether gluteal prominence gives a false impression of increased lumbar lordosis, an apparent lordosis (APL) measurement was taken, measuring the distance from the subject's greater trochanter to the most posterior aspect of the buttocks. No significant differences were found in ALS or ALL between 25 black and 27 white adult female subjects (ALS, P = 0.26; ALL, P = 0.41). Significant differences were found between black and white APL, with blacks demonstrating a larger APL than whites (P less than 0.01). A high correlation was noted between ALS and ALL in both blacks (0.70, P less than 0.01) and whites (0.77, P less than 0.01). The investigators therefore contend that the clinician's assumption that blacks have a greater lordosis than whites is based on an apparent increased lordosis due to more prominent buttocks (APL).