228 



Organ of Hearing. 



308. The Auricle, 

 Auricula. 



309. The Muscles of the 

 Auricle. 



The pinna or auricle is 

 formed by a layer of fibro-carti- 

 lage; its external rim is called 

 the helix, which commences as 

 Spina helicis ; to the inner side of 

 the helix is the fossa of the 

 helix or Fossa scaphoidea ; inter- 

 nal to that, the curved antihelix, 

 the commencement of which is 

 formed by two ridges, the Crura 

 furcata. The deepest concavity of 

 the pinna, surrounding the entrance 

 to the external auditory meatus 

 is called concha. In front of 

 the concha, and projecting back- 

 wards over the meatus is the tra- 

 gus; opposite it the antitra- 

 gus; between both is a deep 

 notch , the Incisura intertragica. 

 Below the notch is the lobule, 

 Lobulus auriculae, devoid of the 

 firmness and elasticity of the rest 

 of the pinna. 



The muscles of the auricle 

 are : the M. attollens (levator) auri- 

 culae, the M. attr aliens auriculae 

 and the MM. retrahentes auriculae. 

 Between the projections of the car- 

 tilage of the ear are: the M. helicis 

 major, which arises from the Spina 

 lielicis, and is inserted into the an- 

 terior border of the helix where it is 

 about to curve backwards ; the M. 

 helicis minor at the commencement 

 of the Spina helicis; the M. tragi- 

 cus upon the anterior surface of 

 the tragus ; the M. antitragicusfrom 

 the lower end of the antihelix to 

 the antitragus. The M. transversus 

 auriculae lies at the convex posterior 

 surface of the cartilage of the ear, 

 between the tubercles of the concha 

 and the fossa of the helix. 



