WHEN the coats of an artery become by any means præternaturally distended, when they become wounded, or when they become ruptured in such a manner as to discharge and deposit their former contents under the neighbouring integuments, under the aponeurosis, or tendinous expansion of a neighbouring muscle, or still more deeply under the muscles themselves; the natural consequence attending this accident will sooner or later be a degree of elevation, or tumor: which species of tumor is known by the term aneurism.
If a true aneurism happens, that is, a swelling arising from a general weakness of the coats of an arterial vessel, or from a wound or rupture of some of its coats, it may be often distinguished from a tumor proceeding from any other cause by a degree of pulsation, supposing the situation of the injured vessel be superficial; as may be evinced in recent aneurisms of the humeral artery, which sometimes happen from bleeding near the bending of the elbow-joint; as well as in aneurisms of the inferior part of the radical artery, of the ulnary artery, or of the anterior artery of the leg called tibialis antica; and as may be observed to be sometimes the case too in those arteries, whose situations are not superficial; to wit, in aneurisms of the aorta ascendens, the curvature of the aorta, and of the carotides.
The symptom of pulsation in tumors, which take their rise from a partial wound, or from a general weakness, and subsequent dilatation of the coats of an artery, is not confined to this species of aneurism, but is frequently attendant upon false aneurisms (that is, such tumors, as are occasioned by extravasated arterial blood), supposing the disease to be a recent one of either of the preceding vessels, or of any other arterial vessel not deeply situated: and this symptom of pulsation in false aneurisms will sometimes be accompanied with a discoloration, or variegated appearance, of the integuments dependent upon the insinuation of the blood underneath them.
But if the extravasation be confined under an aponeurosis, or if the disease has been of so long standing, as to admit of the thinner parts of the extravasated blood being absorbed, or by any other means dispersed, and the fibrous parts, which are left behind, should be accumulated in considerable quantities, and acquire so compact and solid an appearance, as to resemble brown macerated leather in their colour and texture, which I have always observed to be the case in old diseases of this kind; under these circumstances, the original symptoms of pulsation on the swelling, and a discoloration of the integuments, for the most part become imperceptible: for which reasons the true nature of the disease must be attended with a degree of uncertainty.
It must be acknowleged by all those, whose experience has given them opportunities of examining into these diseases, that the symptoms of a pulsation, and a discoloration of the teguments from extravasated blood, are not only very often wanting in old aneurisms, but in the most recent ones: which proves the non-existence of these symptoms to be no certain characteristics of tumors not being aneurismal: and the reason why this often happens may be readily explained, and conceived of, from demonstrating the very deep or low situation of many arteries, that are known to be liable to these injuries; such as the femoral arteries, the arteriæ tibiales posticæ, the arteriæ peroneæ, and some others.
Notwithstanding I have treated of pulsation on tumors, and a discoloration of the integuments or coverings of the part, when they do exist, as being the truest marks of aneurisms; yet it must not be inferred from what has hitherto been advanced, that the appearances of these symptoms are unexceptionable rules of tumors being aneurismal; seeing it does happen, that mere imposthumations, or collections of matter, arising from external as well as from internal causes, are sometimes so immediately situated upon the heart itself, and at other times upon some of its principal arteries, as to partake in the most regular manner of their contraction and dilatation (systole and diastole).
Some years ago I saw an instance of a boy, about 13 years of age, who had his breast-bone much broken by a fall. On this account he was admitted into Guy's Hospital; but not till a fortnight after the accident happened.
Upon examination, there appeared an evident separation of the broken parts of the bone, which were removed at a considerable distance from each other: the intermediate space was occupied by a tumor of a considerable size: the integuments were of their natural complexion: the tumor had as regular a contraction and dilatation as the heart itself, or the aorta could be supposed to have.
Upon pressure, the tumor receded; upon a removal of the pressure, the tumor immediately resumed its former size and shape. All these are the distinguishing signs of a true recent aneurism. The situation and symptoms of this swelling were judged sufficient reasons for considering the nature of the disease as uncertain; on which account it was left to take its own course. The event was, the tumor burst in three weeks after his admittance, discharged a considerable quantity of matter, and the patient did well.
From what has been above advanced it is plain, if these arguments can be supported by facts, that the laying down such rules for infallibly distinguishing aneurismal tumors from tumors proceeding from very different causes, must be a matter of the greatest difficulty: and, as a further proof of their uncertainty, I take the liberty of offering the following short history of a remarkable case, which has lately occurred in my own experience.