THE AUDITORY APPARATUS 



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 aperture on the posterior wall called the 

 apertura tympanica canaliculi chorda through which the chorda 

 tympani nerve enters the tympanum. 



The anterior wall is narrow, because the medial and lateral 

 walls converge anteriorly. The upper part of the anterior wall 



Recessus epitympanicus 





Membrana 

 flaccida 



Anterior and pos- 

 terior malleolar 

 folds 



'endon of tensor 

 tympani (cut) 

 Handle of 

 malleus 



Membrana 

 tympani 



Tympanic sulcus 



FIG. 210. 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. ) 



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 is called the processus cochkariformis ; it serves 

 as a pulley round which the tendon of the tensor tympani 

 muscle turns abruptly, in a lateral direction, towards the 

 malleus. 



On the medial wall, which intervenes between the 

 tympanum and the labyrinth, there are eminences, depressions, 



