EXTERNAL EAR. 363 



Function. To bring the ear forward. This muscle rests 

 upon the temporal vessels, nerves, and fascia. 



Posterior auris, arises from the mastoid process by two 

 or three fasciculi, and is inserted into the back part of the 

 concha. Function. To draw the ear backward and en- 

 large the meatus. 



The proper or intrinsic muscles of the external ear re- 

 ceive their names from the prominences to which they are 

 attached, as the major lielicis, minor Jielicis, tragicus, anti- 

 tragicuSj transversus auriculce. 



Major helicis is a small band of muscular fibres lying 

 upon the superior border of the helix. 



Minor helicis is below the last, and posterior upon the 

 helix, at its commencement in the concha. 



The Tragicus covers the cartilage of the tragus. 



The Anti-tragicus reaches from the anti-tragus to the 

 posterior part of anti-helix. 



Transversus auriculae, situated on the posterior surface of 

 the pinna, 'extends transversely from the concha to the 

 helix. These muscles are very feeble in man, and scarcely 

 to be recognized; but in most quadrupeds they are well 

 developed, and capable of altering, with ease and rapidity, 

 the form and direction of the auricle. 



Meatus auditorius externus is a tube extending from the 

 lower part of the concha, inward to the membrana tym- 

 pani. It is about an inch and a quarter in length, and 

 has its external half cartilaginous the remainder osseous. 

 Its direction is curved, leading first forward and upwarfl, 

 then backward; and by pulling the ear backward and 

 upward, the canal can be straightened, and the membrana 

 tympani seen. The upper and posterior part of the meatus 

 consists of dense fibro-celliilar tissue, extending from the 

 concha to the osseous part of the canal. The osseous por- 

 tion of the meatus in the child is simply a bony ring, and 

 is much shorter. In the adult, it forms the anterior and 

 inferior walls of the meatus externus, and also an investing 

 sheath to the styloid process, being separated from the 

 glenoid cavity, by the fissure of Glasser. 



