I486 



HUMAN ANATOMY. 



Ligaments of the Auricle. — The extrinsic ligaments of the auricle, those 

 which attach the auricle to the temporal bone, form a more or less continuous mass 

 of fibres. These are separated somewhat arbitrarily and described as the anterior 

 and posterior ligaments. The anterior ligament extends from the helix and the 

 tragus to the root of the zygoma. The posterior ligament extends from the emi- 

 nence of the concha and ponticulus to the anterior part of the mastoid process. A 

 number of bands of fibrous tissue, the instrinsic ligaments, bind the parts of the 

 cartilage together. 



The Muscles of the Auricle. — These include the extrinsic and the intrinsic 

 muscles. 



The extrinsic muscles of the auricle, those which extend from the head to the 

 auricle and move it as a whole, have been described under the muscular system 

 (page 483). They are the anterior, superior and posterior auricular muscles. 



The intrinsic muscles, six in number, consist of small strands of muscle-fibres 

 attached to the skin, which extend from one part of the auricle to another and are 



confined to the auricle itself. Of these, 



Fig. 1245. ^^^^^ ^^^ ^^ ^^^ external surface of the 



auricle and two on the cranial. 



1. The smaller muscle of the helix 

 {m. helicis minor) lies upon the crus helicis 

 and the beginning of the helix, its fibres 

 running obliquely upward and forward. 



2. The greater muscle of the helix 

 {in. helicis major) arises from the spine of 

 the helix and extends upward along the 

 anterior border of the helix and is inserted 

 into the eminence of the triangular fossa. 



3. The muscle of the tragus (in. tragi- 

 cus) is a flat muscle on the outer surface of 

 the tragus ; usually only its vertical fibres 

 are distinguishable. Occasionally a separate 

 bundle of muscular fibres {m. pyramidalis) 

 extends from the tragus to the spine of the 

 helix. Likewise another band, the ni. in- 

 cisures Santorini, sometimes called the 

 dilatator conchcr, bridges the greater incisura 

 Santorini. Both of these, however, belong 

 to the system of the tragus muscle. 



4. The muscle of the antitragus {m. 

 antitragicus) is attached to the outer surface 

 of the antitragus. Its fibres run obliquely 

 from the antitragus upward and backward 

 and are inserted into the caudate process of 



Incisura 

 terminalis 



Plate of tragus 



Incisurae 

 Santorini 



Cartilaginous 

 canal 



Bony canal 



Dissection showing bony and cartilaginous portions of 

 right external auditory canal ; seen from in front. 



the helix. On the cranial surface of the auricle are the transverse and the oblique muscles. 



5. The transverse muscle (;«. transversus) bridges over the fossa antihelicis and extends 

 from the eminence of the scaphoid fossa to the eminence of the concha. 



6. The oblique muscle (;«. obliquus), considered by Gegenbauer as a part of the trans- 

 verse muscle, extends from the back of the concha to the eminence of the triangular fossa. 



Actions. — Duchenne and Ziemssen found that by stimulating the muscles of the tragus and 

 antitragus the external auditory canal was narrowed. Duchenne further demonstrated that the 

 greater and lesser muscles of the helix were antagonistic to those of the tragus. The transverse 

 muscle and the oblique muscle by their contraction are said to cause a slight flattening of the 

 auricle. 



Vessels of the Auricle. — Arteries. — The auricle receives its blood supply 

 from branches of the superficial temporal artery and the posterior auricular artery, 

 and thus indirectly from the external carotid. The superficial temporal sends three 

 branches to the outer surface of the auricle: (a) the artery of the helix to the 

 ascending part of the helix, fossa triangularis and the superior crus of the anti- 

 helix; (Ji) the artery of the crus helicis to the region of the crus helicis; {c) the 

 artery of the tragus to the region of the .tragus and lobule, the lobule receiving 



