44 HEAD AND NECK 



turned downwards and backwards to the superior nuchal line. 

 When that has been done the dissector should examine the 

 auricle of the external ear, and familiarise himself with its 

 various parts before he commences the dissection of its extrinsic 

 muscles. 



Auricula. The auricle consists of a thin plate of yellow 

 fibro-cartilage, covered with integument. It is fixed in posi- 

 tion by certain ligaments, and possesses two sets of feeble 

 muscles viz., one group termed the extrinsic muscles, passing 

 to the cartilage from the aponeurosis of the epicranius and 

 the mastoid process, and a second group in connection with 

 the cartilage alone, and therefore called the intrinsic muscles. 



The wide and deep depression which leads into the 

 external acoustic meatus is the concha. The ridge behind 



FIG. 14. The Auricle. 



the concha is the antiJielix. It commences below, in a 

 prominence called the antitragus. From the antitragus it 

 curves upwards behind the concha, and it divides above into 

 two crura which enclose a small depression called the fossa 

 triangularis. Below the antitragus is the lobule, which forms 

 the soft inferior extremity of the auricle. Its posterior 

 border is continuous with the helix, which forms the 

 incurved margin of the auricle. The helix ascends from 

 the lobule to the summit of the auricle ; then it descends, 

 forming the anterior border of the upper part of the auricle, 

 and, finally, it turns downwards and backwards above the 

 external meatus, into the concha, which it partly divides into 

 upper and lower portions. The part of the helix attached 

 to the lobule is the tail of the helix (cauda helicis) and the 

 part which passes from the anterior border of the auricle to 

 the floor of the concha is the crus helicis. The depression 

 which lies between the helix and the antihelix is the scaphoid 



