Differences in Sacral Angulation and Lumbosacral Curvature in Black and White Young Men and Women

Abstract

The angle between the base of the sacrum and its pelvic surface (SA), and the lumbosacral curve (LSC) defined as the anteroposterior distance between the L₁ vertebra and the sacrum were studied in 105 fresh cadavers aged 15–32 years at death. The sample is comprised of 27 black males, 20 black females, 37 white males and 21 white females. Measurements of the SA were made with an adjustable protractor with an accuracy of ±1°. A new method using a specially designed instrument was developed for taking LSC measurements. A sliding scale that could be moved in the cranialcaudal direction was fitted with a measurement stick which measured the depth of the lumbar and sacral vertebral bodies (ventral to dorsal). The measuring device was placed on the autopsy table above the supine cadaver to measure these depths from the ventral side. The LSC was calculated as the mean difference between lumbar and sacral depths. The SA is smaller in black than in white men (43.6 ± 3.4 vs. 61.7 ± 2.1°, p <0.001). Similarly, black women have a smaller SA than white women (36.0 ± 2.2 vs. 50.2 ± 1.9°, p <0.001). The LSC is also larger in black than white men (9.4 ± 1.1 vs. 5.1 ± 0.3 cm, p <0.001), and black women also have significantly larger LSC compared to white women (13.2 ± 0.5 vs. 9.2 ± 0.6 cm, p <0.001). These data are so far the largest empirical evidence of differences in the SA and the LSC in young black and white cadaver specimens.