TYMPANIC CAVITY 



tympanicus into the tympanic antrum, and below this, close 

 to the medial wall, is a small hollow conical projection termed 

 the pyramid. This is perforated, on its summit, and the 

 aperture leads into a canal which curves posteriorly and then 

 downwards until it opens into the lower part of the last 

 stage of the canalis facialis. The curved canal of the pyramid 

 lodges the stapedius muscle, the delicate tendon of which 

 enters the tympanic cavity through the aperture on the 

 summit of the pyramid. Lateral to the pyramid is the aper- 



Recessus epitympanicus 



Membrana 

 flaccida 



Anterior and pos- 

 terior tympano- 

 malleolar folds 

 -Tendon of tensor 

 tympani (cut) 

 Handle of 

 malleus 



Membrana 

 tympani 



FIG. 235. Left Membrana Tympani and Recessus Epitympanicus viewed 

 from within. The neck and head of the malleus have been removed to 

 show the membrana flaccida. (Howden. ) 



ture on the posterior wall called the apertura tympanica cana- 

 liculi chordce. through which the chorda tympani nerve enters 

 the tympanum. 



The anterior wallis narrow, because the medial and lateral 

 walls converge anteriorly. The upper part of this wall is 

 occupied by the opening of the tensor tympani canal ; the 

 intermediate part by the tympanic orifice of the auditory tube ; 

 and the lowest part is a lamina of bone which separates the 

 tympanic cavity from the carotid canal. The tympanic end 

 of the septum between the auditory tube and the tensor 

 tympani canal, the processus cochleariformis, serves as a pulley 



