The stapedial artery in the rat. A microscopical study under normal conditions and in otitis media with effusion.

Arteria stapedialis in the rat was studied in healthy rats and in experimental otitis media with effusion (OME). The mean diameters of the vessel was calculated to approximately 460 microns (healthy) and 430 microns (otitic) (no significant difference). The tunica intima consisted of an endothelium and a well-developed elastica interna. The tunica media was composed of 2-3 layers of smooth muscle cells. The adventitia was thicker than the media and consisted of bundles of collagen fibers. The artery in the middle ear cavity was quite naked covered only with the middle ear mucosa. The stapedial artery did not appear to be involved in the production of effusion in experimentally induced OME.