THE EXTERNAL EAR 329 



sense of pain. Many people who have been deprived of the sense 

 of smell (by disease or injury) assert that they no longer possess 

 the sense of taste, or that, if present, it is greatly impaired. 



THE SENSE OF HEARING 



The organ of the sense of hearing is the ear. It has three 

 divisions: external, middle, and internal (Fig. 210). 



The external ear is that part which is on the outside of the 

 skull, it includes the auricle and the auditory tube. The expanded 

 portion, mostly of cartilage covered with skin, is the auricle; the 



Fossa -iirli -SMi- Fossa 



Lobule 



FIG. 209. THE EXTERNAL EAR. (Morris.) 



deepest depression is the concha, and the opening at the bottom 

 of the concha leads to the external auditory canal (or meatus). 



This auditory canal is one and one-quarter inches in length, 

 formed partly by the cartilage of the auricle and partly by the 

 temporal bone. It curves slightly upward, and then downward 

 and forward. It is lined with skin which bears stiff hairs in the 

 outer portion, and contains the glands which secrete "ear wax" 

 (ceruminous glands). It is important to remember the length and 

 direction of this canal. 



The membrane at the end of the canal is called the membrana 

 tympani, or membrane of the drum. It is a fibrous membrane 



