[Angles of the base of the skull in chimpanzees]

Ten angular measurements have been retained for a study of the basis of the skull for two species of chimpanzees : Pan troglodytes (83 skulls) and Pan paniscus (179 skulls). Were especially studied : growth and sexual or specific differences. Classical parameters or angles measured in reference to the horizontal vestibular axis were used. The statistical study clearly shows the phenomenom of negative rotation with an ontogenic accentuation of quadrupedia.