CARTILAGE 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. The pinna may now be detached by cutting it close to the 

 bone. When the integuments are entirely taken off, the cartilage of the 

 pinna will be apparent ; but in removing the integuments, the lobule of 

 the ear, which consists only of skin and fat, will disappear as in fig. 8. 



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

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

 posteriorly in the antihelix about the middle of the pinna ; whilst ante- 

 riorly a small process projects from it, and there is a fissure near the pro- 

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

 one of these is pointed, and is joined by the helix, the other is continued 

 into the antitragus. On the posterior aspect of the concha is a strong 

 vertical process of cartilage. 



Inferiorly the cartilage is fixed to the margin of the external auditory 

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

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

 part the canal is closed by fibrous tissue. 



In the piece of cartilage forming the under part of the meatus are two 

 fissures (Santorini), one is at the base of 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 



