DISEASES OF THE ARTERIES - pathology we become acquainted with inflammatiom of the lining membrane of the arteries, but, as yet, it has received no clinical history ; its occurrence is, indeed, so rare, that the obser vation which may associate the history with the post-mortem appearances, must be rather a matter of accident than one which can be fairly regarded as a subject of study. It is certainly very remarkable that the inflammatory action so often observed on the valves of the heart, and not unfrequently associated with patches of inflammation on the endocardial membrane, should so rarely extend to the arteries.
Aneurism is, in its early beginnings, also unknown to us in a clinical point of view ; there is nothing in the history of its de velopment characterizing the disease in such a manner as to be of avail in diagnosis. There is little to be learned regarding it beyond the fact that a swelling has been, at some period, disco vered by the patient, or that symptoms have occurred which might be explained by the hypothesis of aneurism, when no swelling has bftn observed.
Its diagnosis resolves itself into a consideration of the circum stances proving the existence of a tumor, of the evidence of its pulsation, and of the disturbances produced in the circulation, especially in the development of an arterial bruit. When these points can be made out distinctly, there is no difficulty in forming a correct opinion of the case. In many instances, however, from the position of• the diseased artery, the information is obtained with difficulty, or is very imperfect ; and then careful examina tion and correct reasoning can alone conduct us to a trustworthy explanation of the phenomena : a hasty observer is liable either to overlook the disease altogether, or to misinterpret the meaning of the symptoms which he has discovered.
§ 1. Superficial Aneurum.—When occurring in a tolerably superficial artery, the disease commonly falls under the care of the surgeon. Mistakes are less likely to occur than when it is deep-seated ; the pulsation and the bruit are both pretty readily made out ; and when by pressure on the artery, at the proximal side of the tumor, it c,ollapses, and is rendered flaccid by the sac becoming partially emptied, the diagnosis is simple and distinct.
In a more advanced stage, when from large deposits in its inte rior the sac has become hard and firm, it is especially important to note that the pulsation is felt when a finger is placed on each side, because an elastic tumor lying over an artery very generally pulsates outwards, but not so as to be felt transversely across the course of the vessel. The arterial bruit may also be simulated by the pressure of a tumor on a perfectly healthy vessel, espe cially in those conditions of blood which embarrass the diagnosis of diseases of the heart, by producing cardiac murmurs. A tu mor lying over an artery must, from its very position, be, to a certain extent, movable, or at least its point of attachment to the deeper tissues does not correspond with the known course of the artery ; and this serves as a further guide in diagnosis.
In superficial aneurism we may sometimes be guided by the history of sudden appearance after a strain, and the mode in which it first revealed itself to the patient's consciousness; but to these much importance cannot attach. It seems scarcely possible that cellular inflammation and abscess lying over an artery should be mistaken for aneurism.
§ 2. Thoracic Aneurinn.—It is unnecessary to repeat the indi cations by which we may arrive at the conclusion that a tumor of some sort exists in the cavity of the chest (see Chapter XX, § 10); we have only to consider here by what circumstances we may be led to believe that it is of the nature of aneurism. And in forming this judgment the pathological facts connected with the disease are not to be forgotten : such as its relative frequency at the c,ommencement and arch of the aorta, and the c,onsequent probability of its being found at the upper and front part of the chest; its tendency to cause absorption or erosion of tissues by pressure, and hence the frequency with which it is attended by pain; hence, too, its termination by hemorrhage before it has attained any such dimensions as are seen in cases of malignant growth : nor may we forget the necessary disturbance of the cir culation, and the constant accompaniment of hypertrophy of the heart.