Is Lesser petrosal a branch of?

The glossopharyngeal nerve gives the impoant branch-the tympanic branch also called the Jacobson&;s nerve. It leaves the inferior ganglion and enters middle ear through the tympanic canaliculussituated at the bony edge between the jugular foramen and carotid canal. It forms the tympanic plexus over the promontory of the middle ear.The tympanic plexus gives off the lesser petrosal nerve and twigs to tympanic cavity, auditory tube, and mastoid air cells.Reference: Textbook of anatomy, Head neck, and brain, Vishram Singh, 2nd edition, page no.345