76 THE EUSTACHIAN TUBE, BY PROFESSOR RUDINGER. 



only folded at certain definite points, at that part where the 

 auxiliary fissure commences, folds of the membrane project be- 

 tween it and the safety tube, which present individual varia- 

 tions both in form and size. In the greater number of cases 

 the lateral fold is stronger than the median ; but the opposite 



Fig. 291. Transverse section from the middle third of the Eusta- 

 chian tube of Man. 1, 2, Cartilage ; 3, musculus dilatator tubse ; 



4, mucous membrane in folds beneath the hook of the cartilage ; 



5, slightly elevated mucous folds of the accessory fissure ; 6, sub- 

 mucosa. 



condition may also be met with, and so far as regards these 

 folds they are incapable of effecting the complete closure of the 

 safety tube. This first becomes possible at that part where 

 the curvature of the uncinate process becomes sharp, and the 

 mucous membrane is no longer so intimately connected with 

 the cartilage. This point is situated at about the middle of 

 the length of the Eustachian tube; here the mucous membrane 



