Bony Auditory Tube and Otitis Media with Effusion

Abstract

The author has for 25 years manually probed the malleus handle for indications of middle ear pathology. Dissection of the bony auditory tube (BAT) and isthmus comprised 120 fresh autopsy and 26 anatomically prepared temporal bones. The semicanal lamina was not completely ossified in all infants and children and 52% of adults. The tensor tympani muscle was edematous and prolapsed into the superior portion of the BAT in eight ears with otitis media with effusion. Infants and children have the tendon of the tensor tympani muscle inserting into the neck of the malleus at an angle of 60° or greater, possibly explaining the relatively large muscle bulk. It is suggested from these autopsy findings that the BAT and isthmus lumen is a functional 2-way channel for air superiorly and mucus streaming interiorly. Manual palpation of the cartilaginous auditory tube in infants did not suggest malacia.