The anatomical relationships of eustachian tubes with and without infection

In a study of 24 human temporal bones, 20 did not show any evidence of infection, whereas 4 showed signs of chronic otitis media (i.e. central perforations of the ear drum) and 1 had a cholesteatoma as well. The eustachian tubes were removed in toto, and fixed in paraffin blocks. Serial sections were cut and the histological and anatomical features studied. No significant (anatomical) differences were found between the tubes with and without infection. In addition, the isthmic lumen of each tube was compared with the mastoid pneumatisation of its temporal bone in an attempt to evaluate the functional status of eustachian tubes with and without infection. The isthmic lumen was chosen for comparison since it is that part of the eustachian tube which offers the highest resistance to air flow. No correlation was found to exist between the isthmic lumen and mastoid pneumatisation parameters of the groups.