Functional anatomy of the tensor veli palatini muscle and Ostmann's fatty tissue.

This study examined morphological features of the tensor veli palatini muscle (TVPM) and Ostmann's fatty tissue that may be important for eustachian tube (ET) ventilation. Histologic sections through the midcartilaginous ET from 17 human temporal bone-ET specimens (age range. 3 months to 88 years) were used to assess 1) the presence or absence of attachment of the TVPM fibers to either the perichondrium of the ET cartilage lateral lamina (LL) or a tendinous membrane along the medial margin of the TVPM, 2) the angular relationship between the TVPM fibers and the vertical axis of the ET lumen, and 3) the location of the TVPM and Ostmann's fatty tissue. The TVPM fibers were attached to the LL perichondrium in 14 cases; an attachment was absent in 3 cases because of fatty atrophy of the TVPM. However, the TVPM fibers were inserted into the tendonlike membrane in all cases. The angle of insertion of TVPM fibers into the membrane was significantly more acute (relative to the vertical ET axis) in the inferior aspect than in the superior aspect of the membrane both in young children (3 months to 4 years; mean +/- SD, 39.0 degrees +/- 15.1 degrees superiorly to 23.8 degrees +/- 17.0 degrees inferiorly) and in older subjects (8 to 88 years, 30.4 degrees +/- 11.6 degrees superiorly to 15.7 degrees +/- 11.2 degrees inferiorly; t-test, p < .001). The location of Ostmann's fatty tissue accompanied the TVPM throughout the cartilaginous ET. These data suggest that contraction of the TVPM moves the LL inferolaterally to open the superior aspect more than the inferior aspect of the lumen and that Ostmann's fatty tissue will limit the opening of the ET lumen, especially that of its inferior aspect.