1486 



HUMAN ANATOMY. 



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

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

 ,,i fibres, These are separated somewhat arbitrarily and described as the anterior 

 and posterior liganu-ms. The anterior ligament extends from the helix and the 

 tra-us 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, 



FlG four are on the external surface of the 



auricle and two on the cranial. 



1. The smaller muscle of the helix 

 (m. helicis minor} lies upon the cms helicis 

 and the beginning of the helix, its fibres 

 running obliquely upward and forward. 



2. The greater muscle of the helix 

 (in. he/ids 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 in. in- 

 cisurce Santorini, sometimes called the 

 dilatator concha, bridges the greater incisura 

 Santorini. Both of these, however, belong 

 to the system of the tragus muscle. 



4. The muscle of the antitragus (in. 

 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 



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



5. The transverse muscle (in. fransversus) bridges over the fossa antihelicis and extends 

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



6. The oblique muscle (in. ob/iquns}, considered by Gegenbauer as a part of the trans- 

 verse muscle, extends from tin- bark of the concha to the eminence of the triangular fossa. 



Actions. I )urhciine and /.iemssm found that by stimulating the muscles of the tragus and 

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



. i and lesM-r nmseles c it tin- helix wen- antagonistic to those of the tragus. The transverse 

 intisel.- ,md the ol>li.|iie 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 tin- Mipertinal temporal artery and the posterior auricular artery, 

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

 branches to tin- outer surface' of the- auricle: (a) the artery of t lie helix to the 



i.lin^ part of the helix, fossa triangularis and the superior cms of the anti- 

 helix: < /' .' th- ," A ;T <>/'///< ,-rns hdnis to the region of the crus helicis; (c) the 

 ,ntii\' <>/ Hie li-ii^u* to the region of tin- tragus and lobule, the lobule receiving 



Plate of tragus 



Cartilaginous 



i-an.il 



Bony canal 



Dissection showing l>ony and cartilaginous portions of 

 right external auditory canal ; seen from in front. 



