CAKTILAGE OF AURICLE. 47 



of the same part, and is inserted into the front of the helix, where this is 

 about to curve backwards. It is usually present. 



The transverse muscle of the auricle (fig. 8, 6 ) forms a wide layer, which 

 is situate at the back of the ear in the depression between the helix and 

 the convexity of the concha. It arises from the convexity of the carti- 

 lage forming the concha, and is inserted into the back of the helix. The 

 muscle is mixed with much fibrous tissue, but it is well seen when that 

 tissue is removed. 



Actions. These muscles are said to alter slightly the condition of the 

 outer ear ; the muscles of the helix assisting, and those of the tragus and 

 antitragus retarding the passage of sonorous undulations to the meatus. 



Dissection. Tl^pinna may now be detached by cutting it close to the 

 bone. When the i^eguments are entirely taken off, the cartilage of the 

 pinna will be appare^j. but in removing the integuments, the lobule of 

 the ear, which consistn^nlpof skin and fat, will disappear as in fig. 8. 



The cartilage of tnepimvQ, (fig. 8) resembles much the external ear in 

 form, and presents nearlyLheVsame parts. The rim of the helix subsides 

 posteriorly in the antihel^*ilJout the middle of the pinna ; whilst ante- 

 riorly a small process proj^JJs from it, and there is a fissure near the pro- 

 jection. The antihelix is dfjHtled, about two-thirds down into two pieces ; 

 one of these is pointed, and js^joified by the helix, the other is continued 

 into the antitragus. On the$ft>pst^rior aspect of the concha is a strong 

 vertical process of cartilage. ' J 



Interiorly the cartilage is fixed^o ($he margin of the external auditory 

 aperture in the temporal bone, and'foFms part of the meatus auditorius ; 

 but it does not give rise to a com^jjpte tube, for at the upper and outer 

 part the canal is closed by fibrous tfisue. 



In the piece of cartilage formingr*J) under part of the meatus are two 

 fissures (Santorini), one is at the bas^bf the tragus, the other passes from 

 before backwards. 



Some ligaments connect the pinna with the head, but others pass from 

 one point of the cartilage to another. 



The external ligaments are condensed bands of fibrous tissue, and are 

 two in number, anterior and posterior. The anterior fixes the fore part 

 of the helix to the root of the zygoma. The posterior passes from the 

 back of the concha to the mastoid process. The chief special ligament 

 crosses the interval between the tragus and the beginning of the helix, 

 and completes the tube of the meatus. 



The FACIAL NERVE (portio dura, fig. 9), or the seventh cranial nerve, 

 confers contractility on the muscles of the face. Numerous communica- 

 tions take place between it and the fifth nerve ; the chief of these are 

 found above and below the orbit, and over the body of the lower jaw. 



Dissection. The facial nerve is to be displayed on the right side of the 

 face if there is time sufficient before the body is turned, otherwise it is to be 

 omitted for the present (see p. 17). Some of the nerve is concealed by the 

 parotid gland, but the greater part is anterior to the glandular mass. 



To expose the ramification of the nerve beyond the parotid gland, let 

 the skin be raised from the face in the same manner as on the left side. 

 The different branches are then to be sought as they escape from beneath 

 the anterior border of the gland, and are to be followed forwards to their 

 termination. 



The highest branches to the temple have been already partly dissected 

 above the zygomatic arch ; and their junctions with the temporal branch 



