THE AURICULAR MUSCLES 749 



poral bone. Thoso are united l)y elastic membranes to form a complete tube. Its 

 calliper diminishes from without inward, so that the lumen of the inner end is about 

 half of that of the outer end. 



The skin on th(^ convex surface of the concha presents no special features; it 

 is attached to the cartilage by a considerable amount of subcutaneous tissue except 

 at the apex. The integument which lines the concave surface is intimately ad- 

 herent to the cartilage and is relatively dark in color. There are three or four 

 cutaneous ridges which run about parallel with the borders of the conchal cartilage, 

 but do not extend to the apex or the cavum conchse. The upper and marginal 

 parts and the ridges are covered with long hairs, but between the ridges and below 

 it is thin, covered sparsely with very fine hairs, and supplied with numerous 

 sebaceous glands. In the external auditory canal the skin becomes thinner; in 

 the cartilaginous part it is su]:)plied with numerous large, coiled, ceruminous glands 

 (Glandulae ceruminosse) and is sparsely covered with very fine hairs; in the osseous 

 part the glands are small and few or absent and there are no hairs. 



THE AURICULAR MUSCLES 



The auricular muscles may l^e subdivided into two sets, viz., (a) extrinsic 

 muscles, which arise on the head and adjacent part of the neck, and move the ex- 

 ternal ear as a whole, and (6) intrinsic muscles, which are confined to the auricula. 

 In this connection the scutiform cartilage may be regarded as a sesamoid cartilage 

 intercalated in the course of some of the muscles. 



The extrinsic muscles are as follows: 



1. The scutularis is a thin muscular sheet situated subcutaneously over the 

 temporalis muscle. Its fibers arise from the zygomatic arch and the frontal and 

 sagittal crests, and converge to the scutiform cartilage. It consists of three parts. 



(a) The fronto-scutularis comprises temporal and frontal parts, which arise 

 from the zygomatic arch and the frontal crest, and are inserted into the outer and 

 anterior borders of the scutiform cartilage respectively. 



(6) The interscutularis arises from the sagittal crest, over which it is in part 

 continuous with the muscle of the opposite side. Its fibers converge to the inner 

 border of the scutiform cartilage. 



(c) The cervico-scutularis is not well defined from the preceding muscle. It 

 arises from the occipital crest and is inserted into the inner border of the scutiform 

 cartilage. 



2. The anterior auricular muscles (Aim. auriculares nasales) are four in number. 

 (a) The zygomatico-auricularis arises from the zygomatic arch and the parotid 



fascia, and is inserted into the outer face of the base of the conchal cartilage under 

 cover of the parotido-auricularis. 



(h) The scutulo-auricularis superficialis inferior arises on the outer part of 

 the superficial face of the scutiform cartilage and ends on the base of the conchal 

 cartilage with the preceding muscle. 



(c) The scutulo-auricularis superficialis medius arises from the posterior part 

 of the deep surface of the scutiform cartilage and is inserted into the dorsum of the 

 conchal cartilage, close to the lower part of its anterior border and above and behind 

 the preceding muscle. It receives a sli]~» from the cervico-scutularis. 



(d) The scutulo-auricularis superficialis superior is a thin sli]) which is de- 

 tached from the interscutularis over the inner border of the scutiform cartilage. 

 It ends on the anterior aspect of the lower part of the dorsum of the conchal car- 

 tilage. 



3. The superior auricular muscles (!\Im. auriculares dorsales) are two in 

 number. 



(a) The scutulo-auricularis superficialis accessorius is a narrow band which is 



