[A functional assessment of the masticatory muscles in mammals and humans].

We have amended and added to Fabian's tables giving a functional assessment of individual masticatory muscles. The data in our tables refer only to the temporalis, masseter, pterygoideus medialis, pterygoideus lateralis and digastricus muscles. The weights of these muscles were determined in three fixed human cadavers and the mean values compared with those of apes, carnivores, herbivores and rodents. In humans, the most powerful masticatory muscle is the M. temporalis, followed by the M. massater, as in apes and carnivores. The M. pterygoideus is also one of the most important. This is remarkable, since in the other groups this muscle occupies the last place. This relative strengthening of the M. pterygoideus lateralis is an important characteristic of the human masticatory apparatus. In humans, the difference between the relative weights of the individual masticatory muscles is not nearly so great as in other mammalian groups. The M. pterygoideus lateralis does lie close behind the other two big adductors (Mm temporalis and masseter) but, as regards power and weight, it hardly differs from the M. pterygoideus medialis and the M. digastricus. In humans the strengthening affects not only the M. pterygoideus lateralis but also the M. digastricus. It would seem that these two masticatory muscles could become the key to the understanding of the specific changes in human mastication.