Elements of Surgery. Robert Liston

good air, out-of-door exercise, and attention to diet, are of material importance. Frequently advantage will result from the patient’s sleeping on a hard mattress; and, in bad cases, from lying down, when tired, on an inclined plane.

      In great softening, it will be necessary to confine the patient entirely to the recumbent position, and to support the head and shoulders by a light and firm machine. The causes, symptoms, appearances, and treatment of caries of the spine, in its different regions, with or without curvature, will be afterwards considered.

OF INFLAMMATORY AND OTHER AFFECTIONS OF THE ARTERIAL SYSTEM.

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      During inflammation of arteries, the actions of the vessels are accelerated and attended with pain; the internal coat is found to be of a red colour, from increase of its vascularity, and not from its being merely tinged with the colouring part of the blood; or it is of a yellowish hue and rough, from the deposition of lymph on its surface, whilst the external coat is thickened by the infiltration of serum and lymph. When bloodvessels are inflamed from mechanical irritation, lymph is secreted on their internal coat, becomes organised, and obliterates their calibre; if deficient in nervous influence and circulating fluid at a particular point, there ulceration of their coats occurs; if violently injured or completely isolated, their coats mortify; and these circumstances must all be calculated on in the surgical treatment of arteries. A universal inflammatory state of the arterial coats is said to have existed, and its symptoms have been minutely detailed; but its occurrence seems to be extremely rare, and the treatment is medical.

      Inflammation is supposed to precede degeneration of the arterial coats. As a person advances in life the arteries lose elasticity, and the heart its balance with them; either the one or the other becomes dilated, their parietes are thickened, and the valves are altered in structure; the enlargement of the vessels is generally greatest towards their origin. The dilatation of arteries, more especially of the internal ones, is often very great; ultimately the internal coat gives way, and the external, with the surrounding tissues, yields in proportion as the blood diffuses itself. The internal tunic is occasionally burst in consequence of violent and sudden muscular exertion; and, even when the vessels are pretty limber and sound, effusion of lymph, and obliteration of the vessel ensue, or, more frequently, aneurism.

      Previously to the rupture of the internal tunic, however, there is, in most cases, a morbid alteration in the texture of the vessel. The internal coat becomes dry; its textures is more dense and less elastic, and consequently more brittle. Morbid matter is deposited between the middle and internal coats, and this, by stretching the latter still further, diminishes the elasticity and cohesion of their texture. The deposit is at first to a slight extent and of soft consistence, somewhat resembling condensed fatty matter. Afterwards it increases in quantity and consistence, becoming, instead of soft and yielding, dense, hard, and incompressible; in short, calcareous.

      Though the morbid deposit is at first confined, as above related, its limits are afterwards extended; calcareous matter is insinuated, either in minute particles or in broad laminæ, amongst the fibres of the middle coat, is also found external to it, and occasionally situated in the cellular coat. In fine, the various component parts of the parietes of the vessel degenerate, according to the degree of advancement which the disease has attained; and such a condition is the predisposing cause to ulceration of the internal coat, and subsequent effusion of blood. The steatomatous, ulcerated, earthy degeneration of the proper coats of an artery, as Scarpa, the celebrated professor of Pavia, has it, are well exhibited in the accompanying sketch.

ANEURISM

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      During violent and sudden exertions the more brittle parts may burst, either at a certain point, or throughout the whole circumference of the artery; and on this such results will supervene as on ulceration of the internal tunic. Ecchymosis then takes place under the cellular coat, which becomes thickened, and incorporated with, and strengthened by, the surrounding tissues; this is the incipient state of an aneurismal tumour. The effusion of blood, gradually increasing, distends the cellular coat, forming the cavity into which it is poured, and produces a tumour of a size proportional to the distensibility of the tunic and the force of the effusion. Sometimes the external coat is separated from the others to a considerable extent by the insinuation of blood. An aneurism, however, may exist from simple dilatation of a portion of the vessel, gradually increasing, and forming a cavity in which the blood accumulates. At one time it was supposed that all spontaneous aneurisms were caused by simple dilatation of the canal; but such an opinion has been long shown to be incorrect, and the term of true aneurism is now confined by many to that tumour and accumulation of blood consequent on the giving way of the internal coat, and situated externally to the canal of the artery. It is true that dilatation may occur previously to the giving way of the coats, and thus the two causes are combined. The dilatation occurs from the calibre of the artery being considerably diminished, in the first instance, at the point where its coats have undergone the calcareous degeneration, and only acts as a predisposing cause to the failure of the coats when thus diseased. When there is mere dilatation, the tumour is generally of an oval form; but when the internal coat gives way, a lateral prominence is formed, and gradually increases in size. The shape of the true aneurism is various: sometimes the tumour is globular, with a narrow neck; and, from this being of considerable length, it becomes difficult, in some situations, as above the clavicle, to ascertain the particular artery which is the seat of disease, the globular extremity of the tumour presenting itself at some distance from the vessel with which its pedicle is connected. This is rare, however. At other times its form is very irregular, being most prominent at the part where the accumulation of the blood is least resisted. Pulsation in the tumour is distinct from the first, and is painful to the patient; and in the external aneurisms it is so strong as to be perceived by a bystander at a considerable distance. The tumour is at first compressible, and completely disappears on firm pressure being applied, either directly to the sac, or to the artery above, the sac being thereby emptied of its contents, or prevented from being filled. It may sometimes be difficult to form an accurate diagnosis, from the circumstance that tumours, not aneurismal, receive a pulsatory movement from an artery or from arteries immediately beneath them; such difficulty is obviated by attention to this simple test—that in an aneurism the pulsation is felt equally in all directions. Besides, if the tumour is moveable, it can be partially displaced, so as not to lie immediately over a large artery, and, if it be not aneurismal, it will then be found to possess no pulsation; if it be an aneurism, its pulsation will not be diminished by any change of position.

      The blood contained within the aneurismal sac, being comparatively motionless, coagulates, and the coagulum is attached to the inner surface; at first it contains red globules, but it afterwards loses them, and becomes of a pale hue, consisting solely of fibrin. This coating gradually increases, and attains no small thickness, fresh portions of fibrin being superadded in concentric laminæ. These layers are chiefly deposited from the blood within the cavity, but they also appear to receive addition from lymph being effused by the vessels proper to the original parietes of the tumour. By such thickening, it can be easily conceived that the pulsation will be somewhat lessened. In large aneurisms the accumulation and deposit of fibrin may be much greater at some points than at others, and hence pulsation may be rendered “not equal in all directions.” It is not, however, diminished to any great extent; for absorption of one or more points occurs, and the coating is again attenuated.

      In some rare cases the deposition of fibrin has gone on gradually accumulating, filled completely the aneurismal cavity, and thus effected a spontaneous cure, the remaining solid tumour imperceptibly diminishing by the action of the absorbents. After obliteration of the aneurismal cavity, the fibrin is generally deposited in so great quantity as to occupy the calibre of the vessel above and below the tumour, obstructing the progress of the blood, causing it to flow by the smaller and collateral branches, and effecting a spontaneous