60 SURGICAL APPLIED ANATOMY. [Ch ap . v. 



entirely absent. In other cases the " fistula " appears 

 merely as a narrow sinus or a depression, running 

 through and from the helix. Accidental removal of 

 the pinna is usually associated with but comparatively 

 little diminution in the acuteness of hearing. 



The skin covering the auricle is thin and closely 

 adherent. The subcutaneous tissue is scanty, and 

 contains but very little fat. In inflammatory condi- 

 tions of the surface, such as erysipelas, the pinna may 

 become extremely swollen and very great pain be 

 produced from the tenseness of the parts. The pinna 

 and cartilaginous meatus are very firmly attached to 

 the skull, so that the body, if not of great weight, 

 may be lifted from the ground by the ears. 



In chronic gout, little deposits of urate of soda 

 (called tophi) are often met with in the pinna, and are 

 usually placed in the subcutaneous tissue at the edge 

 of the helix. M. Paul has pointed out that, when 

 ear-rings are worn, the usual hole made by the ring 

 may become converted into a vertical slit, or the ear- 

 ring ,may cut its way out, leaving a slit in the lobule. 

 This it may do several times if re-applied, thus pro- 

 ducing many slits in the same lobule. He considers 

 such conditions as absolutely diagnostic of scrofula.* 



The external auditory meatus is about 1J 

 inches long. It is directed forwards and inwards, 

 having the same direction as the petrous bone. The 

 external meatus, the promontory, the cochlea, and the 

 internal meatus lie nearly in the same line. The 

 canal has a vertical curve about its middle, with the 

 convexity upwards. To straighten the canal for the 

 introduction of specula and other instruments, the 

 pinna should be drawn upwards and a little outwards 

 and backwards. The osseous part forms a little more 

 than one-half of the tube, and is narrower than the 



* See "Scrofula and its Gland Diseases," by the Author. 

 Loud., 1882. 



