[Studies on the facial muscles in the aged].

The dissection of the facial musculature in the elderly made on 2 bodies, confirmed the mode of evolution noted earlier in the Primates. The reduction in the m. platysma myoides was confirmed; this muscle showed only two parts: a rudimentary pars buccalis and a relatively developed pars mentalis. This reduction was accompanied by fundamental transformations since the m. quadratus of the chin appeared at the anterior part of the pars mentalis of the platysma myoides. The derivatives of the deep m. sphincter coli showed an arrangement very similar to that of the Simians. However some modifications already observed became stronger, particularly the verticilisation of the m. caninus and the separation of the two m. zygomaticus. Curiously, the extrinsic ear musculature persisted and remained well developed despite its absence of activity.