46 HEAD AND NECK 



branches, and the posterior and the posterior part of the superior 

 by the posterior auricular branch. After the auriculares muscles 

 have been denned remove the skin from the entire extent of the 

 auricle to display the cartilage, the ligaments, and the intrinsic 

 muscles. 1 Great care is required to make a successful dissection. 



The auricular cartilage extends throughout the entire auricle, with the 

 exception of the lobule and the portion between the tragus and the helix. 

 Those portions are composed merely of integument, fatty tissue, and 

 condensed connective tissue. The shape of the cartilage corresponds with 

 that of the auricle itself. It shows the same elevations and depressions, 

 and by its elasticity it serves to maintain the form of the auricle. But it 

 also enters into the formation of the cartilaginous or lateral portion of the 

 external acoustic meatus. By its medial margin this part of the cartilage 

 is firmly fixed by fibrous tissue to the rough lateral edge of the auditory 

 process of the temporal bone, but it does not form a complete tube. It is 

 deficient above and anteriorly, and there the tube of the meatus is completed 

 by tough fibrous membrane, which stretches between the tragus and the 

 commencement of the helix. 



In a successful dissection of the cartilage of the auricle, two other points 

 will attract the attention of the student. The first is a deep slit, which 

 passes upwards so as to separate the lower part of the cartilage of the 

 helix, termed the processus helids caudatus, from the cartilage of the anti- 

 tragus. The second is a sharp spur of cartilage which projects forwards 

 from the helix, at the level of the upper margin of the zygoma ; it is 

 termed the spina helicis. 



The Ligaments of the Auricle. The ligaments are three bands of 

 fascia. The anterior passes from the spine of the helix to the root of the 

 zygoma. The superior and posterior are both attached to the cartilage in 

 the region of the concha ; the former blends above with the temporal fascia, 

 and the latter is attached to the mastoid portion of the temporal bone. 



The Intrinsic Muscles of the Auricle. The two muscles of the helix, 

 and the tragicus and the antitragicus, are placed upon the lateral face 

 of the cartilage. The transversus and the obliquus lie upon the cranial 

 surface of the auricle. 



The musculus antitragicus is the best-marked member of the lateral 

 group. It lies upon the lateral surface of the antitragus, and its fibres pass 

 obliquely upwards and backwards. Some fasciculi can be traced to the 

 processus helicis caudatus. 



The musculus tragiciis is a minute bundle of short vertical fibres 

 situated upon the lateral surface of the tragus. When well developed a 

 slender fasciculus may sometimes be observed to pass upwards from it to 

 the anterior part of the helix, where it is inserted into the spine of the helix. 



The musculus helicis major is a well-marked band, which springs from 

 the spina helicis, and extends upwards upon the anterior part of the helix, 

 to be inserted into the skin which covers it. 



The musculus helicis minor is a minute bundle of fleshy fibres which is 

 placed upon the crus helicis as it crosses the bottom of the concha. 



The musciihis transversus auricula is found upon the cranial aspect of 

 the auricle. It is generally the most strongly developed muscle of the 

 series, and its fibres bridge across the hollow which, on this aspect of the 

 auricle, corresponds to the antihelix. 



1 In most cases it will be advisable to defer this part of the dissection till 

 the body is turned on its back for the second time, and to proceed at once to 

 the dissection described on p. 47. 



