DONE, PATHOLOGICAL CONDITIONS OF. 



459 



which a deposit is found between it and the 

 bone, or between the laminae of this membrane. 

 Exostpsis, then, may consist of different struc- 

 tures of cartilage alone of cartilage mixed 

 with some material resembling ligament of 

 cartilage mixed with osseous structure, which is 

 by far most frequent of occurrence of pure 

 bone and lastly, of a much harder, firmer, 

 and closer substance, nearly resembling ivory. 

 It may attack any bone whether flat or round, 

 and may be found in more than one bone at a 

 time : perhaps the femur and the tibia are most 

 frequently engaged. 



Like most other affections of the osseous 

 system, the causes that lead to the production 

 of this disease are involved in the greatest 

 obscurity. Unquestionably they sometimes 

 appear as the results of accident, but then, 

 when other and more severe injuries constantly 

 occur without inducing such a consequence, 

 the unavoidable conclusion must be that some 

 peculiarity of constitution predisposing to the 

 disease exists in the individuals who suffer 

 from it. Exostosis has been seen, though not 

 frequently, at a very early period of life ; it 

 has occurred idiopathically and attacked several 

 bones in the same individual at the same time ; 

 after complete removal it has grown again with 

 an inveterate pertinacity, and we have seen it 

 in two or more individuals of the same family. 

 Boyer* considers the venereal poison to be the 

 most common cause of exostosis, scrofula to 

 have but little connexion with it, and scurvy 

 still less. Other French writersf take a more 

 extensive range, and adduce as causes, accident, 

 cutaneous affections, scrofula, scurvy, cancer, 

 and venereal. We cannot coincide with any 

 of these opinions. Scrofula, when it attacks a 

 bone, produces a destructive caries, and not an 

 adventitious growth; scurvy, a softness or 

 brittleness of bone. If there is any idiopathic 

 disease of bone bearing the smallest resem- 

 blance to cancer, it is osteo-sarcoma, and vene- 

 real or even mercury we suspect to have a 

 closer connexion with caries than exostosis. 



In every form of exostosis, no matter from 

 what cause proceeding, (and we have seen that 

 its exciting causes are sufficiently obscure,) the 

 surface of the bone and its substance to some 

 depth become altered into a structure nearly 

 resembling that of the morbid growth. Patho- 

 logists are not agreed as to whether this altera- 

 tion should be attributed in the first instance 

 to an inflammatory process within the perios- 

 teum or the bone itself. Mr.CramptonJ makes 

 the terminations (as they are technically called) 

 of chronic inflammation of the periosteum to 

 consist in cartilaginous thickening of the mem- 

 brane, absorption of the subjacent bone, or 

 the deposition of an undue quantity of bony 

 matter upon its surface, the first and last of 

 which are evidently forms of exostosis. HOMT- 

 ever, leaving this part of the subject, which 

 after all is not of much practical importance, 

 still unsettled, it may be remarked that whether 



* Traite des Maladies Chirurgicales, torn. iii. p. 



t Diet, des Sciences Medicales, art. Exostose. 

 J Dub. Hosp. Rep. vol. ii. p. 433. 



the morbid action commences in the bone or 

 not, this latter structure is always extensively 

 engaged. Exostosis is seldom to be met with 

 like a circumscribed tumour in the soft parts 

 connected by a narrow neck or bounded by a 

 well-defined base; on the contrary, the bone 

 forms a considerable portion of the swelling, 

 which generally seems to spring gradually from 

 an extended portion of its surface. 



The symptoms of exostosis may be arranged 

 into those produced by the inflammatory or 

 other diseased action within the bone or perios- 

 teum, and those occasioned by the pressure of 

 the tumour on the adjacent organs. In general 

 it is said not to be very painful nor very sen- 

 sitive to the touch, but this opinion must be 

 received with great limitation. We have wit- 

 nessed the case of a young gentleman who had 

 exostosis on the front of both tibiae. Here was 

 neither nerve to be compressed nor muscle to 

 be interfered with, yet the pain was so great 

 that he insisted on their removal. The part 

 was as hard and firm as ivory, and removed 

 by the mallet and chisel. His sufferings were 

 extreme : he was subsequently attacked with 

 erysipelas, and his life brought into extreme 

 danger, yet did he not regret his pain and the 

 risk he ran when considered as the price of the 

 relief he had obtained. The pain in this case 

 could not be regarded as the result of pressure 

 on any very sensible structure. 



However, the situation of the tumour may 

 not only occasion a great aggravation of suffer- 

 ing, but be the cause of very formidable occur- 

 rences. We have seen a very small exostosis, not 

 larger than half a marble, prove the apparently 

 exciting cause of epilepsy, which for years 

 embittered the patient's existence, and at length 

 brought it to a termination. Indeed, it can 

 scarcely be necessary to adduce instances in 

 order to prove that morbid growths from the 

 internal table of the skull may prove detrimen- 

 tal or even destructive in a variety of ways. 

 Such growths from the bottom of the orbit very 

 generally destroy vision by protruding the eye 

 from its socket; from the maxillae they may 

 interfere with respiration or deglutition; and 

 in any situation where there are muscles, they 

 must more or less change their direction or 

 otherwise impair their motions. But beyond 

 this they cannot be considered as malignant 

 they do not involve adjacent structures in a 

 disease similar to themselves, they do not 

 ulcerate, neither do they contaminate the sys- 

 tem through the medium of the absorbents. 

 The vascular organization of an exostosis seems 

 to be inferior to that of the bone from which 

 it springs, and to the healthy structures whether 

 bone or cartilage that it may appear to resem- 

 ble; its growth is therefore in general slow and 

 its size moderate ; but its increase is progressive, 

 and there is no limit to the size it may ulti- 

 mately attain, in this respect differing from the 

 node, which soon attains its proper dimensions 

 and does not increase subsequently. The same 

 deficiency of organization causes it to endure 

 an attack of inflammation but badly, and 

 therefore, when subjected to any irritation or 

 even exposed to the influence of the atmos- 



