Craniofacial anomalies in the Upper Missouri River over a millennium: archeological and clinical evidence.

Congenital facial clefting occurs more often in Native Americans from the Upper Missouri River Basin (UMRB) than it does in the general population. However, no facial clefts were seen in 3,750 ancient UMRB skeletons. Very few reports concerning defective palate crania are in the literature of paleopathology. Findings regarding craniofacial anomalies in today's native Americans in the UMRB are presented briefly and compared to those in skeletons from this region. There is a marked difference between the frequency of anomalies which occurred in the past and those which are present today. Although the people sampled here were from many cultures and lived during different time periods, encompassing over a millenium, the fundamental denominator was a common geographic location. Reasons for the differences between the past and the present are advanced. It may be possible to estimate the frequency of anomalies which have not been found in archeological specimens but which are present today. By comparing data concerning "occult" congenital anomalies of the past with those of the present, the actual prevalence of past cranio-facial anomalies may be estimated through careful extrapolation.