STRUCTURE OF THE PINNA. 



73 



the concave side. In the external auditory meatus these reappear in a modified 

 form as the ceruminous glands. The hairs of the pinna are most numerous and 

 longest on the tragus and antitragus. The hairs on the margin and convex aspect 

 of the ear are arranged with a general tendency to point towards the tubercle of 

 Darwin, where the converging series may even form a distinct tuft, thus furnishing 

 an additional argument in favour of the view regarding the meaning of that promi- 

 nence which was taken by Darwin. 



crus helicis 



helix 



fossa scaphoidea _ 



spina helicis - 



anthelix i 



free edge of trar/u* _-, 



incisura Santorhn J 



tragus plate 



end of cartilage of - 

 meatus 



Fig. 80. EAR-CARTILAGE, ANTERIOR ASPECT. (Arnold.) 



The cartilage (figs. 80 to 82) forms a plate 1 mm. to 3 mm. thick, with all the 

 inequalities already described as apparent on the outer surface of the pinna, and on its 



antitragus 

 a 



processus caudalis 

 b 



-. spina helicis 



incisura Santorini 



Fig. 81. EAR-CARTILAGE, LATERAL ASPECT. (Schwalbe.) 



In the natural position of the parts the corner of the tragus plate ** fits into the angle marked * at 

 the anterior part of the helix. Between a and b, the isthmus separating the auricle-cartilage from the 

 cartilage of the meatus. 



cranial surface having prominences the reverse of the concha and the fossa of the helix, 

 while between these is a depression in the situation of the anthelix. The cartilage 

 is not confined to the pinna, but enters likewise into the construction of the outer 

 part of the external auditory canal. When dissected from other structures, it is 



