THE EXTERNAL EAR 



1123 



exhibits a transverse furrow, the sulcus antihelicis transversus, which separates the prominence 

 produced by the concha from that caused by the fossa triangularis. A vertical ridge (pon- 

 ticulus) upon the eminentia conchae gives attachment to the Retrahens aurem muscle. The 

 fissure of the helix is a short vertical slit, situated at the fore part of the pinna. Another fissure, 

 the fissure of the tragus, is seen upon the anterior surface of the tragus. Anteriorly and infe- 

 riorly the cartilage of the pinna is continuous with the cartilage of the external auditory meatus 

 by a cartilaginous isthmus (isthmus cartilaginis auris). Some authors regard the tragus as 

 part of the cartilage of the meatus. The cartilage of the pinna is very pliable, elastic, of a yel- 

 lowish color, and belongs to that form of cartilage which is known under the name of yellow 

 fibrocartilage. 



The ligaments of the pinna (ligamenti auricularia [Valsalvae]) consist of two sets: 1. The 

 extrinsic set, or those connecting it to the side of the head. 2. The intrinsic set, or those 

 connecting the various parts of its cartilage together. The extrinsic ligaments, the most 

 important, are three in number superior, anterior, and posterior. The superior ligament 

 (ligamentum auriculare superius) extends from the suprameatal spine to the spine of the helix. 

 The anterior ligament (ligamentum auriculare anterius) extends from the spina helicis and 

 tragus to the root of the zygoma. The posterior ligament (ligamentum auriculare posterius) 

 passes from the posterior surface of the concha to the outer surface of the mastoid process of 

 the temporal bone. The chief intrinsic ligaments are: (1) A strong fibrous band stretching 

 across from the tragus to the commencement of the helix, completing the meatus in front, and 

 partly encircling the boundary of the concha; and (2) a band which extends between the anti- 

 helix and the cauda helicis. Other less important bands are found on the cranial surface of the 

 pinna. 



The muscles of the pinna (Figs. 830 and 832) consist of two sets: (1) The extrinsic, which 

 connect it with the side of the head, moving the pinna as a whole viz., the Attollens, Attrahens, 

 and Retrahens aurem (p. 366). (2) The intrinsic, which extend from one part of the auricle 

 to another viz.: 



Helicis major. 

 Helicis minor. 

 Tragicus. 



Antitragicus. 

 Transversus auriculae. 

 Obliquus auriculae. 



The Helicis major (m. helicis major) is a narrow vertical band of muscle fibres, situated upon* 

 the anterior margin of the helix. It arises, below, from the spina helicis, and is inserted into 

 the anterior border of the helix, just where 

 it is about to curve backward. 



The Helicis minor (m. helicis minor) is 

 an oblique fasciculus which covers the 

 crus helicis. 



The Tragicus (m. tragicus) is a short, 

 flattened band of muscle fibres situated 

 upon the outer surface of the tragus, the 

 direction of its fibres being vertical. 



The Antitragicus (m. antitragicus) ariies 

 from the outer part of the antitragus; its 

 fibres are inserted into the cauda helicis 

 and antihelix. This muscle is usually 

 very distinct. 



The Transversus auriculae (m. trans- 

 versus auriculae) is placed on the cranial 

 surface of the pinna. It consists of scat- 

 tered fibres, partly tendon and partly 

 muscle, extending from the convexity of 

 the concha to the prominence correspond- 

 ing with the groove of the helix. 



The Obliquus auriculae (Tod) (m. 

 obliquus auriculae) consists of a few fibres 

 extending from the upper and back part 

 of the concha to the convexity immediately 

 above it. 



The arteries of the pinna are the pos- 

 terior auricular from the external carotid, 

 the anterior auricular from the temporal, 

 and an auricular branch from the occip- 

 ital artery. The veins of the pinna ac- 

 company the corresponding arteries. The F IO _ 832 The muscles of the pinna. 



