「In the tympanic cavity, the tympanic nerve (a branch of CN IX) divides into branches which, along with sympathetic fibres from the carotid plexus, form the tympanic plexus. This plexus is located on the surface of the promontory.
This tympanic plexus gives off:
The branches of the tympanic cavity provide innervation to the mucosa of the middle ear. The lesser petrosal nerve provides autonomic parasympathetic fibers that eventually innervate the parotid gland.」