Anatomy of the auditory tube and related structures in the rhesus monkey (<i>Macaca mulatt</i><i>a</i>)

Abstract

The primate nasopharynx-auditory tube-middle ear complex is being used by several researchers to model both normal and pathologic functions of the human auditory tube. An extensive search of the literature has indicated little detailed information on the primate tube/middle ear system. This study was undertaken to define the anatomical characteristic of the system in the rhesus monkey (Macaca mulatta) and to determine the limits on the use of the monkey as a model of human tubal function. Although the direct application of morphologic data to account for the observed function of a system is a tenuous one, the data on the rhesus monkey auditory tube appear to be consistent with those published for other mammals. The tensor veli palatini muscle appears to be the only muscle to act directly on the tube and effect tubal dilation. The muscle is attached to the lateral membranous tubal wall along its extrabullar extension. The muscle has an inferior attachment to the posterior hard palate and thus possesses a vector directed inferolaterally; contraction would appear to pull the membranous wall inferiorly and laterally, resulting in tubal dilation. The auditory tube relationships of the salpingopharyngeus, levator veli palatini, and internal pterygoid muscles are described. Their possible role in primate tubal function is minimal at best.

Morphology of the Middle Ear in the Rhesus Monkey (<i>Macaca Mulatta</i>)

“…The auditory tube findings were not included since they have been recently dis cussed in detail by Doyle and Rood [1979],…”

Structure of the Middle Ear and Auditory Tube in the House Musk Shrew, <i>Suncus murinus</i>

“…In S. murinus, however, there is no anatomical evidence that the TVP has any role in the AT function. This difference between S. murinus and other animals [Misurya, 1976;Doyle and Rood, 1979] arises from the different topographical relationships of the muscles to the AT. The lack of bony enclosure of the ME and AT, short AT and complex shape of the tubal cartilage in S. murinus may exclude the TVP from the AT.…”

“…Anatomical and physiological investigations on the TVP, LVP and SA of the dog [Rich, 1920;Honjo et al, 1979] and rhesus monkey [Cantekin et al, 1979[Cantekin et al, , 1983Doyle and Rood, 1979] indicate that the TVP is the only muscle responsible for the active tubal opening. In S. murinus, however, there is no anatomical evidence that the TVP has any role in the AT function.…”

“…The enclosure of the ME in S. murinus is a thin, inflated covering of connective tissue with a bassinetshaped framework, resembling that of monotremes [Novacek, 1977] and other insectivores [Novacek, 1977]. While detailed information concerning the ME and AT musculature of man [Graves and Edwards, 1944;Proctor, 1973;Williams et al, 1989], rat [Hebel and Stromberg, 1976;Albiin et al 1983] and rhesus monkey [Doyle and Rood, 1979] is available, these muscles are poorly known in S. murinus. For research workers, an understanding of the structural and functional relationships of this musculature is essential.…”

Structure of the Palate and Pharynx in the House Musk Shrew <i>(Suncus murinus)</i>

“…It forms no part of the palatine aponeurosis, nor does it originate in the sphenoid in contrast to that of marsupials [Kostanecki, 1891], rhesus monkeys [Doyle and Rood, 1979] and man [Körner, 1942;Romanes, 1981;Williams et al, 1989]. The TVP and tensor tympani in S. murinus are connected through a common tendon, but not by muscle fibers.…”