Acta Medica Medianae
MORPHOLOGICAL STRUCTURE OF THE BONY PART OF THE EUSTACHIAN TUBE AND ITS CLINIC AND SURGICAL IMPORTANCE
Dragoslava ĐERIĆ and Miodrag DINIĆ
Institute for Otorhinolaryngology and Maxillofacial Surgery of the Clinic Center, Belgrade and Otorhinolaryngological Department of the Military Hospital, Belgrade
The bony part of the Eustachian tube or protympanum was examined by the anatomic and histological methods on 200 temporal bones of the grownups. This part of the tube is on average 11,3 mm long, while its tympanic inlet is of 5,2 x 3,9 mm. The tube's lumen can be of irregular shape (45%), rectangular (35%) and triangular (20%). The external wall of the protympanum makes a part of the tympanic bone. The medial wall is made up of two parts, namely, the posterolateral (labyrinth) and anteromedial (carotid). In 2% of the cases, the bony wall above a. carotis is missing in the internal one so that it projects itself into the tube's lumen. The medial part of the tube's upper part is made of the bony septum towards m. tensoris tympani while the lateral one represents a part of the tegment timpani. The lower wall of the protympanum corresponds to the joint of its external and the internal walls; most often it is in the form of a shallow groove. The morphological variations in the structure of the Eustachian tube's bony part are important in the formation of some pathological states of the middle ear as well as in the microsurgical interventions of this region.
Key words: Bony part of the Eustachian tube, morphological structure, clinic importance