To guide surgery of nerves that traverse and surround the tympanic cavity in the rat, anatomical
illustrations are required that are topographically correct. In this study, maps of this area are presented,
extending from the superior cervical ganglion to the otic ganglion. They were derived from observations that
were made during dissections using a ventral approach. Major blood vessels, bones, transected muscles of
the tongue and neck and supra and infrahyoid muscles serve as landmarks in the illustrations. The course of
the mandibular, facial, glossopharyngeal, vagus, accessory and hypoglossal nerves with their branches, and
components of the sympathetic system, are shown and discussed with reference to data available in the
literature. Discrepancies in this literature can be clarified and new data are presented on the trajectories of
several nerves. The course of the tympanic nerve was established. This nerve originates from the
glossopharyngeal nerve, enters the tympanic cavity, crosses the promontory, passes the tensor tympani
muscle dorsally, and continues its route intracranially to the otic ganglion as the lesser petrosal nerve after
intersecting with the greater petrosal nerve. Auricular branches of the glossopharyngeal and of the vagus
nerve were noted. We also observed a pterygopalatine branch of the internal carotid nerve, that penetrates
the tympanic cavity and courses across the promontory.