Tympanic cavity Tympanic cavity The tympanic cavity is a small cavity surrounding the bones of the middle ear. Within it sit the ossicles, three small bones that transmit vibrations used in the detection of sound. On its lateral surface, it abuts the external auditory meatus [ ear canal ] from which it is separated by the tympanic membrane (eardrum). The tympanic cavity is bounded by: It is formed from the tubotympanic recess, an expansion of the first pharyngeal pouch. If damaged, the tympanic membrane can be repaired in a procedure called tympanoplasty. Should fluid accumulate within the middle ear as the result
Basilar membrane membrane is also the "base" for the sensory cells of hearing, the hair cells that are equipped with "Stereocilia". There are approximately 15,000 hair cells in each human ear (see figure). This function as base of the sensory cells gave the "basilar" membrane its name, and it is again present in all land vertebrates. Due to its location, the basilar membrane places the hair cells in a position where they are adjacent to both the endolymph and the perilymph, which is a precondition of hair cell function. A third, evolutionarily younger, function of the basilar membrane is strongly developed in