A marked asymmetry was reported in the sacral alae of the Neandertal individual Regourdou 1 from southwest of France. Using metric analysis, we quantified the sacral asymmetry of Regourdou 1 which was then compared to a modern human sample.
Regourdou 1 shows left-side asymmetry of the sacral alae which is caused by an underdeveloped right ala. The condition substantially exceeds directional asymmetry of a modern human population.
Possible interpretations are proposed to explain this condition with particular emphasis on a probable developmental origin.