Topographical anatomy and morphometry of the temporal bone of the macaque

Based on the dissections of 24 bones of 12 macaques (Macaca mulatta), a systematic anatomical description was made and measurements of the chosen size parameters of the temporal bone as well as the skull were taken. Although there is a small mastoid process, the general arrangement of the macaque's temporal bone structures is very close to that which is observed in humans. The main differences are a different model of pneumatisation and the presence of subarcuate fossa, which possesses considerable dimensions. The main air space in the middle ear is the mesotympanum, but there are also additional air cells: the epitympanic recess containing the head of malleus and body of incus, the mastoid cavity, and several air spaces on the floor of the tympanic cavity. The vicinity of the carotid canal is also very well pneumatised and the walls of the canal are very thin. The semicircular canals are relatively small, very regular in shape, and characterized by almost the same dimensions. The bony walls of the labyrinth are relatively thin.