MUSCLES OF THE EXTERNAL EAR 



311 



triangular cartilaginous plate situated in the front of the base of the 

 concha, to which it is attached. The cartilages of the ear are for the 

 purpose of collecting and transmitting sound to the essential organ of 

 hearing within the temporal bone, and to effect this purpose they, and 

 especially the concha, require to be moved in various directions. This 

 is effected by means of the following muscles, which are connected with 

 them : 



Zygomatico-Aurieularis. This comprises two thin slips of muscle 

 arising from the zygomatic process of the squamous temporal bone. They 



Fig. 372. Muscles of the Ear. 

 (Anterior aspect ; outer and deep layers. ) 



Fig. 373. Muscles of the Ear. 

 (Lateral aspect.) 



ra 



Fig. 374. Muscles of the Ear. 

 (Posterior aspect.) 



1, Temporalis. 2, Parieto-auricularis interims. 3, Parieto-auricularis externus. 4, Scuto-auricularis 

 interims. 5, Zygoniatico-auricularis. 6, Scutiform Cartilage. 7, Scuto-auricularis externus. 8, Corru- 

 gator Supercilii. 9, Parotido-auricularis. 10, Splenius. 11, Tendon of Sterno-cleido-mastoideus. 12, Mas- 

 seter. 13, Cervico-auricularis externus. 14, Cervico-auricularis medius. 15, Obliquus Capitis Superior. 



become inserted into the scutiform cartilage, and into the outer and inferior 

 part of the concha. 



Action. To draw the ear forward. 



ParietO-Auricularis Externus. A broad, thin muscle spread over 

 the superior part of the forehead and covering the temporalis muscle. 



Origin. From the parietal crest or bony ridge in the centre of the 

 forehead. 



Insertion. By two slips, one to the inner margin of the scutiform 

 cartilage and the other to the inner and anterior part of the conchal 

 cartilage. 



Action. To draw the ear inwards and direct the opening forward, as 

 when " pricked ". 



ScutO-Auricularis Externus. This muscle attaches the scutiform 

 cartilage to the inner side of the concha. It assists in drawing the ear 

 inwards and directing the opening forward. 



