Morphology, function, and clinic of the Eustachian tube.

Diagnostic and treatment of diseases of the Eustachian tube are difficult d ue to the deep position underneath the skull base and its oblique course. S everal theories exist explaining the normal and disturbed function. Few suf ficient tests for functional evaluation exist. Gross anatomical and microsc opical features of the Eustachian tube gained from 30 sectional series were correlated with radioanatomical findings of high resolution magnetic reson ance tomography (MRT) of 29 adult persons without ear disease. Differences to MRT of 31 patients with tubal disease or disturbed ear ventilation were evaluated. Tubal cartilage (Tt), musculus tensor veli palatini (MTVP), and Ostmann's fat pad have a characteristical shape, that is correlated to norm al function. The zone of physiological tubal closure is found in the vicini ty of the isthmus. For precise imaging of these anatomical tubal structures using of special simple or double angulation of MRT-planes is necessary. O pen tube disease often shows a typical atrophy of the Ostman's fat pad in t he physiological closing zone. Causes of obstruction are found in different parts of the tube. Atrophy and hypertrophy of mucous membrane are also sho wn as a pathogenetic factor. In many cases disturbed function of the Eustac hian tube is correlated to impaired anatomical structures which may be iden tified by MRT. Treatment should be planned according to afflicted structure s. A synopsis of anatomy, physiology, and clinical characteristics is prese nted.