70 SuKGrcAL APPLIED ANATOMY. [Chap. v. 



the cleft. In these congenital fistulpe, when well 

 marked, the pinna is cleft just in front of the tragus, 

 or through the helix, and there is more or less failure 

 in the closing of the meatus and tympanum, while the 

 membrana tympani will be more or less deficient, or 

 entirely absent. In other cases the " fistula " appears 

 merely as a narrow sinus or a depression, running 

 through and from the helix. Some of the smaller and 

 more superficial fistulas are due not to a defective 

 closure of the branchial cleft, but to want of complete 

 fusion between certain of the tubercles from which 

 the pinna is primarily developed. Accidental removal 

 of the pjnna is usually associated with but compara- 

 tively 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 vei'tical 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 \\ 

 inches long. It is directed forwards and inwards, 



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

 Lond. 1882. 



