[Morphological findings of the tympanic plexus].

A morphological study of the human tympanic plexus was performed. The tympanic nerve patterns on the promontory were classified into two types. The first was the single nerve trunk type, the second the type of nerve which divides into anterior and posterior branches. A tubal branch and a caroticotympanic branch on the promontory were both present in about 90% of the ears studied. Many ganglion cells were distributed on the tympanic plexus. It was concluded that these ganglia were autonomic, based on the nature of their fine structure. We speculate that these ganglia are parasympathetic and that they modulate the functions of vasodilators and secretory glands in the mucosa of the middle ear. In addition, we conducted a fiber analysis of the tympanic nerve and the lingual branch of the glossopharyngeal nerve and made a comparison between them.