TIIK KAIJ 



.ALLY WRITTEN 11V Al.THtU IIl\^\l\V, F.K.C.S., AND AliTHCR KODINSON, M.l>. 



M.R.C.S. REVISED AND LARGELY RKWHITTI-\ 

 Mv AMKA.M T. KKIJK. M.S.. .M.I). 



OF ANATOMY IN Tin: I'IIKM i.i. i MVEESITT MF.D1CAL COt I.EGE 



The auditory organ, or car, is divided into three parts external, middle, and 

 internal. 



THE EXTERNAL EAR 



The external ear consists of the auricle attached to the side of the head, and 

 the external acoustic (auditor}-) meat us leading from it to the middle ear (fig. 747). 



THE AURICLE 



The auricle, or pinna, presents a lateral and a- medial surface. The lateral sur- 

 face is irregularly concave (fig. 745), the deepest part of the concavity, the concha, 

 being partially divided by an oblique ridge, the crus of the helix, into a superior 



Fio. 745. LATERAL SURFACE OP THE LEFT ArmrLE. 



CRURAOFANTHELIX 



Crus or the helix 

 Anterior incisure 



Supratratjic tubercle 



TRAGUS 

 Intertraffic incisure _AB 



HELIX 



Auricular tubercle 



Triangular foua 

 MUM 



CYMBA 



CONCH* 



UVUM 



ANTHELIX 



Posterior auricular Bulcua 



HELIX 



ANTITRAGUS 



part, the cymba conchae, and a larger inferior part, the cavum conchae. This lat- 

 ter is directly continuous with the acoustic incatus, and is bounded ventrally by a 

 prominent process, the tragus, which projects dorsally and overhangs the entrance 

 to the meat us. The tragus. which has a small tubercle on it superiorly, the supra- 

 tragic tubercle, is separated from the crus of the helix by a well-marked depression, 

 the anterior incisure. Mounding the cavum concha? dorsally and inferiorly is a 

 projection, the antitragus, which is situated opposite, but inferior, to the tragus. and 

 between the two is a deep notch, the intertragic incisure. Mounding the concha 

 dorsally and superiorly is a prominent semicircular ridge, the anthelix, ending in- 



1049 



