STRUCTURE OF THE EAR 



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within the middle is absorbed and the inequality of pressure 

 thus produced causes deafness. 



The tympanum is a thin elastic membrane covered 



Fig. 51.— Auditory organ (diagrammatic, after Schafer) ; 1. Auditory 

 nerve ; 2. internal auditory meatus ; 3. vitricle ; 5. saccule ; 

 fi. canalis media of cochlea ; 9. vestibule containing perilymph ; 

 12. stapes; 13. fenestra rotunda; 14. pinna; 16. external 

 auditory meatus; 17. membrane tympani; 18. malleup ; 19. 

 incus ; 23. Eustachian tube. 



externally by skin and internally by mucous membrane. 

 The fibres composing it are arranged circularly and radially. 

 Along part of its inner surface is attached the handle of 

 the malleus, the outermost of the three ossicles. 



