MTSG'LES OF THE PINNA. 75 



Muscles. Of the muscles of the pinna, those which are attached by one end to 

 the side of the head, and move the pinna as a whole, have been already described 

 (Vol. II.) : there remain to be examined several smaller muscles, composed of thin 

 layers of pale-looking fibres, which extend from one part of the pinna to another, 

 and may be named the, special muscles of the organ. Six such small muscles are 

 distinguished ; four being placed on the outer and two on the inner or deep surface 

 of the pinna. 



The smaller muscle of the helix (fig. 83, 1) is a small bundle of oblique fibres, 

 lying over, and firmly attached to, that portion of the helix which springs from the 

 bottom of the concha. Like the other of these muscles, its fibres are, in part, 

 attached to the skin. 



The greater muscle of the helix (2) lies vertically along the anterior margin of the 

 pinna. By its lower end it is attached to the spine of the helix ; and above, its 

 fibres terminate opposite the point at which the ridge of the helix turns backwards. 

 The anterior auricular muscle is sometimes continued partly into this muscle. 



Fig. 83, A and B. OUTER AND INNER SURFACES OF THE RIGHT PINNA, EXPOSED TO SHOW THE SMALL 



MUSCLES (from Arnold). 



1, musculus helicis minor; 2, m. helicis major ; 3, tvagicus ; 4, antitragicus ; 5, musculus transversus 

 auriculae ; 6, musculus obliquus auriculae. 



The muscle of the tragus (3) is a flat bundle of short fibres covering the outer 

 surface of the tragus : its direction is nearly vertical. Occasionally a slender bundle 

 of muscular fibres is seen prolonging this muscle across the cleft in the cartilage 

 between the tragus and fore part of the helix to be attached to the spine of the helix 

 (m. pyramidalis, Jung). Another muscle (dilatator conchce, Theile) of less constant 

 occurrence lies upon the anterior face of the tragus, bridging over the greater fissure 

 of Santorini, which is there present. 



The muscle of the antitragus (4) is placed obliquely over the antitragus and 

 behind the lower part of the anthelix. It is fixed at one end to the antitragus, 

 from which point its fibres ascend somewhat to be inserted into the caudate process 

 of the helix, above and behind the lobule. 



The transverse muscle (5) lies on the inner or cranial surface of the pinna, and 

 consists of radiating fibres which extend from the back of the concha to the promi- 

 nence which corresponds with the groove of the helix. 



The oUique muscle (Tod) (6) consists of a few fibres stretching from the back 

 of the concha to the convexity directly above it, across the back of the inferior 

 branch of the anthelix, and near the fibres of the transverse muscle. 



The muscles of the tragus and antitragus tend to contract the entrance to the meatus 

 when stimulated by electricity (Duchenne), the muscles of the helix having a contrary ten- 

 dency. They are none of them under the influence of the will, but it is possible they may act 

 slightly in a reflex manner. All the ear- muscles are supplied by the facial nerve. 



