NO. 6 EAR EXOSTOSES HRDLICKA 45 



For Kaufmann, MoUer-Holst says, exostoses and hyperostoses are 

 but form-differences. " Marx, too, knows no boundaries between cir- 

 cumscribed exostoses and diffuse hyperostoses, and no more does 

 Alexander, who uses the two terms for the same growths." Moller- 

 Holst's own view is that, though there exist all kinds of transitions 

 between the bony growths in the ears in their form as well as their 

 structure, yet from the clinical point of view there is a justification 

 for subdivisions of the formations on the basis of location, shape, 

 and size. " Speaking generally, therefore, a so-called bony polyp of 

 the meatus may anatomo-pathologically be an exostosis or a hyper- 

 ostosis " — which last statement is not very clear. 



New observations. — It is plain from the above that a generally valid 

 classification of the abnormal bony ear growths has not been realized 

 and in fact, appears to be unrealizable ; but that clinically there is a 

 prevalent sense of two or rather three forms — the diffuse or broad- 

 based irregular tumefactions ; the circumscribed, occasionally peduncu- 

 lated tumors, capable of a rapid growth and, together with their soft 

 coverings, of causing an occlusion of the whole canal; and small 

 indolent rarely troublesome " ceiling " growths in the meatus. 



The extensive examinations reported in this monograph lead to the 

 conclusion that, aside from the small, more or less pearllike exostoses — 

 or probably better osteomata — arising from the superior or squamous 

 part of the meatus, there is no line of demarcation that would permit 

 any valid subdivision of the growths into hyperostoses and exostoses, 

 or in any other manner. There are many cases where a clear charac- 

 terization of the growth by one or the other of the above main terms, 

 hyperostosis and exostosis, is impracticable- — it is more or less both. 

 There are other more differentiated cases in which at the base the 

 growth would deserve the name of diffuse hyperostosis, but above this 

 is definitely a more or less rounded exostosis. There are cases where 

 what is evidently the same growth, in the same location, will in one of 

 the ears of the same skull show the form of a pronounced exostosis, 

 in the other that of some grade of hyperostosis or an intermediary 

 condition. And there are no few instances in which both or all three 

 of these forms (hyperostoses, exostosis, and intermediary) may be 

 seen in the same ear. The more or less diffuse hyperostosis of the pos- 

 terior or anterior wall of the meatus is in many cases in all probabiHty 

 but an earlier stage of an exostosis. 



Thus otology, for its practical purposes, will doubtless keep its 



conventional classification of the bony growths of the external auditory 



canal into hyperostoses, exostoses, and osteomata of the roof ; but 



those who use this classification should be aware of the fact that, 



4 



