In a pathological point of view, spina ven tosa should not be considered as a malignant disease : it often endures for a length of time or during life without engaging adjoining structures or contaminating the constitution, and if removed by operation it does not recur in another place or seize on some other bone. It is, moreover, not infrequently capable of relief or even of cure by the simple operation of exposing the cavity and evacuating its con tents We have at this moment before us the details of a case in which the patient referred a spina ventosa of the lower jaw to a blow re ceived years previously, during the last twelve of which the tumour had been opened or given way spontaneously three seve ral times. In hospital it was punctured through the mouth, and found to consist of three dis tinct cells, each containing its own collection of a fluid of the consistence of oil, varying from a straw colour to that of coffee, the darkest being lodged within the largest cell. This patient, though at the advanced age of sixty seven, was relieved by the operation, and left the hospital convalescent. If, hovvever, by the term malignant is meant a disease that may prove destructive of life or Hint), spina ventosa can occasionally lay claim to the title. For it sometimes happens that small dark red or pur ple elevations appear on the surface of the skin, which soon ulcerate and burst, discharging a quantity at first of the material contained within the bone, the character of which subsequently alters into a brown unhealthy, fetid, and often putrid sallies. This ulceration is much more likely to take place when the surface of the tumour is uneven and lobulated, and at this period the disease in appearance bears no very faint resemblance to fungus hwmatodes. The external sores next become fistulous and fun goid ; they lead down to the cavity or cavities within the bone, and the patient, worn and wasted by an ill-formed irritative hectic fever, sinks exhausted arid dies.
Boyer* in his description recognizes these two forms of spina ventosa. " Sometimes," says this author, " having attained a size dou ble or triple that of the natural dimension of the bone, the tumour ceases to make further progress : it no longer causes pain ; it does not interfere with the motions of the part, but re mains stationary, and continues thus during life, without any alteration of the soft parts, which accustom themselves by degrees to the state of distension in which they are placed. I3ut much more commonly it continues to in crease, until it slowly arrives at an enormous size, still preserving its inequalities of surface or acquiring new ones." Having proceeded to the period of ulceration the conclusion of the case is thus delineated. " Arrived at this point, the local disease exercises a baneful in fluence on the constitution of the patient: the edges of the fistulous apertures become de pressed and inverted towards the interior of the tumour ; the discharge becomes every day more copious and more fetid ; the fever which ap pears commonly at the period of ulceration, but vvhich at first is intermittent and irregular, comes at last to be continued, and assumes the character of hectic : the pains are unceasing:, and sometimes intolerable; sleep and appetite are deranged or lost; consumption establishes itself, and the patient dies exhausted and worn out." Other authors, however, have considered spina ventosa in all its forms as a malignant disease. Such must have been the opinion of Mr. B. of Edinburgh, not only from his descriptions, but from the practice he incul cates. " The treatment," he says, " of spina
ventosa is very simple, as the surgeon, when he is insured of its existence, must at once have recourse to the amputating knife. If the dis ease is seated in the hones of the metacarpus or metatarsus, as is generally the case in child hood, they should be removed at the articula tions. If it has attacked the tibia and fibula, or radius and ulna, the amputation may be performed either at the knee or elbow, or a short way above these joints. The general rule to be observed is, that the entire bone in which the disease has its seat should be removed." The morbid anatomy of spina ventosa throws but imperfect light on its pathology, principally because the first and early changes induced by the disease are wholly unobserved, and there fore are we ignorant both of the peculiarity of constitution that disposes to it, and of the local alterations that are first developed. Even at a more advanced period, when an opportunity is afforded of examining the part after death or removal, there is no striking uniformity of ap pearance. The bone itself, as Boyer remarks, seldom seems to have suffered any actual loss of substance : on the contrary, it often appears rather to have gained in wei2,ht, the walls ex panding and becoming thinner in proportion as the cavity within increases in size. As to the number, size, and shape of these cells, there is an infinite variety as well as in the appearance of the surface, which may be smooth, irregular, or lobulated, and in the character of the mein brane lining the cells and the material secreted by it. There is in the museum of the Anato mical School, Park-street, Dublin, a very curi ous specimen, exhibiting a perfect bony cyst developed within a spina ventosa of the supe rior maxilla, and completely contained within the expanded walls of the bone. It is a very remarkable circumstance connected with these alterations of structure, that although they usu ally commence near the extremities of the long bones, they never attack the joints, and conse quently the motions of thc adjacent articulation may be but slightly impaired, even although the size of the tumour may be such as to inter fere with the natural shape of the joint, and render its usual appearance obscure and indis tinct.
employ this term to indicate certain tumours growing from the outer sur face, or rather the external structure of a bone, in the production of which neither the medul lary substance within nor the periosteum with out have any participation. And although our notions of the nature of the disease may not be perfectly-correct, and our descriptions lame and incomplete, we still prefer this arrange ment in order to separate the disease under consideration from spina ventosa on the one hand, and osteo-sarcoma on the other. It will be necessary also to distinguish it from nodes and some other affections of the periosteum, in which a deposit is found between it and the bone, or between the lamiiim of this membrane. Exostosis, then, inay 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.