Racial differences in sacral structure important in caudal anesthesia

The black population of North America is often thought to be quite heterogeneous, because of the admixture of white and Indian blood. But several investigators who measured large numbers of black and white people (alive or as skeletons) showed that the black population was less varied in physical dimensions than the white population. These studies dealt primarily with features of the face and pelvis. Some morphologic features of black people are very stable, and are expressed even when mixed with other races. What causes the structural differences of the sacrums of the two races is not known. A pronounced lumbar lordosis in black people has been well described, and it is assumed that this hyperlordosis is connected with a slightly greater forward tilt of the pelvis. However, the forward tilt is not simply a matter of posture, but rather is determined by structural features of the vertebrae and the pelvis. The results of the measurements may have clinical implications. On the average, in the black patient, the insertion of a needle for caudal anesthesia should be a little easier, because the caudal canal is higher and the needle will be at a steeper angle than in white patients.