The anatomy of the eustachian tube in the rat: A macro‐ and microscopical study

Abstract

The rat eustachian tube (ET), from the nasopharyngeal orifice to the tympanal orifice, is about 4.5 mm long, of which the naso-medial membranous part (the nasopharyngeal orifice) measures about 1.5 mm and the occipito-lateral bony portion about 3 mm. The nasopharyngeal orifice is surrounded by two soft, lip-like, mucosal swellings--one ventral and one cranial--both easily mobile. The muscles related to the tubal opening mechanisms are the salpingopharyngeus, the tensor veli palatini and the levator veli palatini muscles. The salpingopharyngeus muscle originates partly from the cranial lip, whereas the palatal muscles originate partly from the ventral lip. The tympanal two thirds of the mucosal lining of the ET is cranially guided by a cartilage and incompletely framed by bony structures. The tympanal orifice is situated in the nasal part of the medial wall, well above the floor of the bulla. The tensor tympani muscle does not seem to take part in the opening and closing mechanisms of the ET. The mucosal lining of the ET consists of a respiratory epithelium with numerous glands in the lamina propria. It is suggested that the tubal muscles control the passage through the ET by moving the lip-like folds of the nasopharyngeal orifice. The anatomy of the rat ET is comparable to that described in Homo and it can be concluded that the rat ET might be a good model for studying the function of the human ET.

Main trajectories of nerves that traverse and surround the tympanic cavity in the rat

“…We have summarised relevant aspects of the cited literature and supply new data on the tympanic bone that folds inwards at its caudal end, and partly covers the promontory like a shell. For further details, with special reference to the middle ear, see Albiin et al (1983Albiin et al ( , 1986, Van den Berge et al (1990), and Van den Berge & Van der Wal (1990).…”

“…However, the photograph supplied (Furusawa et al 1991 b) shows this latter muscle in the position of the stylopharyngeus muscle as in our Figures 3 and 6. The levator veli palatini muscle is not located there ; it arises from the area around the nasopharyngeal orifice of the auditory tube and the caudal end of the internal pterygoid process, and runs to the soft palate (Albiin et al 1983).…”

The Effects of Gastric Reflux and Artificial Saliva on Eustachian Tube Functions in a Xerostomised Rat Model

“…artar. [24][25][26] Benzer şekilde bu çalışmada da, tüm gruplarda mukosilier epitelin kapladığı alanın ve goblet hücrelerinin yoğunluğunun, timpanik orifis düze-yinde nazofarengiyal orifise göre daha az olduğu tespit edilmiştir.…”

Chemical Carcinogenesis and Nasopharyngeal Carcinoma

“…Subsequently, Albin N et al [53] have systematically studied serial sections of rat nasopharynxes at different ages. They demonstrated that nasopharyngeal epithelium consists of three different kinds of epithelium: pseudostratified ciliated columnar epithelium, stratified squamous epithelium, and transitional epithelium.…”