Spontaneous Varicose Aneurism is the opening or rupture of an aneurism into a vein that has coalesced with it. Cases of this kind have been noticed by myself and many foreign observers in the femoral artery, in the abdominal aorta with the Vena cava inferior, and in the ascending aorta with the Vena cava superior.

The communication established between the artery and the vein is, as we have already remarked, either direct or indirect. The former is frequently observed at the elbow, as a consequence of venesection; thus, for instance, whilst the outer wound of the vein is cicatrizing under a bandage and compress, which prevent the formation of an extravasation into the cellular tissue, the two vessels coalesce together, more especially in the immediate vicinity of the openings of the wounds, by which means a direct communication is formed between them. The vein at the spot presents the appearance of a swelling or roundish expansion, which commonly increases to about the size of a hazel-nut or half a walnut, but, in some rare cases, attains an extraordinary volume (Hodgson, Larrey). The direct communication of the two vessels, and the dilatation of the vein at the corresponding point constitute what is known as aneurysmal varix.

Such a communication between the artery and the vein is always present in spontaneous varicose aneurism.

The indirect mode of communication is effected in the following manner by the presence of a false aneurism. In those cases in which a sufficiently strong compress has not been applied immediately after the injury, and where two vessels have been injured, which are not in immediate contact, or are not fixed in one common layer of cellular substance, or where finally the wounds in each do not originally correspond together, or where, after the injury has been inflicted, the vessels have been displaced or separated, - an extravasation into the cellular tissue is formed, which, in the last-named cases, pushes the vein aside from the artery, and thus prevents the establishment of a direct communication between the two.

This extravasation, - a false diffused aneurism, - is now reduced to a false circumscribed aneurism, the cavity of which forms the medium of communication between the artery and the vein. This false aneurism varies in size, but it commonly is not larger than a walnut or a hen's egg. It generally forms a more considerable and a tougher swelling than that which occurs in a direct communication, and hence Scarpa was led to distinguish this condition from aneurismal varix by the designation of varicose aneurism.

The aneurismal sac presents many differences in reference to the extent to which it lies on the artery, and especially in relation to the opening.

The size of the openings into the two vessels also varies very considerably, and depends, like their form, on the size of the original wound, on the instruments by which the injury was inflicted, etc. The opening in the artery in general permanently retains its original size and form, whilst that in the vein undoubtedly experiences many alterations like the aneurismal sac itself.

The openings in the vessels, as well as the inner surface of the aneurismal sac, are invested with a lining membrane of recent formation, which continuing into the two vessels, gradually loses itself, and merges, more especially in the case of the vein, into the deposit formed upon the inner surface of that vessel. In consequence of this, the openings in the vessels have a smooth and healed appearance.

In the so-called aneurismal varix and in spontaneous varicose aneurism, the communication is effected by means of a simple opening, through the coalescing adjacent walls of both vessels, which acquires a smooth and healed appearance in consequence of being invested with a membrane of recent formation, and thus loses its original character of a rent or rupture.

All observers are unanimously of opinion that the arterial blood principally, if not exclusively, passes into the vein, in both these modes of communication, the direct as well as the indirect. Breschet thinks, that in an operation for a varicose aneurism he also saw the venous blood pass into the artery through the aneurismal sac, during the diastole of the latter. To this circumstance, which may indeed occur in some cases, he refers the dilatation of the arteries below the aneurism, together with the attenuation of the arterial walls, in consequence of their contact with venous blood, - an explanation that has been given by no other observer.

The character of the vessels above and below the place of communication, as indicated by all observers, and as I have repeatedly had occasion to notice, corroborates the existence of a very preponderating current of arterial blood towards the vein. The vein becomes first dilated below the point of communication, and then finally spreads beyond and above it. This dilatation is associated with an enlargement of the valves. The walls of the veins become thicker and more rigid, principally in consequence of the formation of new layers of lining membrane (see p. 205); they at length acquire an appearance similar to that of the arteries. Below the communication the artery is contracted in consequence of the blood being drawn away towards the vein; and its walls then become thinner, relaxed, and more similar to the veins in consequence of the diminished energy of their function, corresponding to the extent to which the blood is drawn away from it. The artery becomes dilated above the communication, in consequence of the obstacle which the venous blood opposes to the entrance of arterial blood into the vein.

The limb below a varicose aneurism is frequently swollen; it also presents a cyanotic color, its cellular tissue is infiltrated and hypertrophied, and the general investment is the seat of repeated erysipelatous inflammations, excessive epidermal formation, etc.

The sequelae of spontaneous varicose aneurism between the trunks of the aorta and of the Vena cava are obvious, but they are often indistinctly manifested in consequence of their being masked by the results of the aneurismal affection of the trunk of the artery, and by the simultaneous presence of heart-disease.

The process of healing and obliteration after arteries have been cut through or tied. - An artery, on being cut through, is immediately retracted in its sheath, - at any rate, as far as the next lateral branch, if of considerable size, while it at the same time becomes gradually contracted. The blood pours outwards in a greater or less quantity, according to the extent and position of the external wound, or it is effused into the cellular tissue. Independently of the aid afforded by art, the exhaustion itself exerts a favorable action on the coagulation of the blood effused around the artery. The coagulum within the canal of the arterial sheath, which is produced by the retraction of the vessel, forms the outer plug, - the most essential and the actual means of arresting the hemorrhage. In addition to this plug, another - the inner plug, is gradually formed within the artery itself, by the coagulation of the blood which is arrested in the stump by the first plug, unless a considerable lateral branch is given off in the immediate neighborhood.

By these means the necessary conditions are obtained for arresting the hemorrhage; and the cure - closure - is then effected by the adhesive inflammation of the cellular sheath of the vessel on the margin of the wound and by the obliteration and final atrophy of the whole stump of the artery, as far as the next collateral branch, in the same manner as we observe after ligature, torsion, etc, and which we will now proceed to consider.

The whole healing process of arteries that have been cut through, has been fully elucidated by the invention of the ligature, and by the numerous investigations in reference to this process, as shown by experiments on animals. The labors of Stilling have thrown the greatest light on this subject in modern times; and we purpose in the following remarks to borrow from them the most important facts, which we will incorporate with our own views regarding individual points of the whole process, as obtained from investigations on the human subject. We would here briefly remark that the alterations resulting from ligature, etc, more especially the formation of thrombus, are more evident at the cardiac than at the peripheral end of the affected artery, and that the following remarks more especially apply to the alterations effected at the former of these points.

After the application of the ligature or torsion, the terminations of the cut artery, as has been already observed, retract. This gradual contraction, which affects the artery as far as the next lateral branch, probably depends, at first, upon the irritation set up by the ligature, and subsequently, on the decrease in the quantity of blood entering this portion of the artery, in consequence of its abstraction towards the dilated branches, and on the diminished impulse. By this contraction of the fibres of the yellow coat the lining membrane of the vessel is wrinkled into delicate longitudinal folds; whilst the whole of the wall of the vessel is puckered into more considerable plaits at the spot where the ligature has been placed.

The ligature or torsion takes the place of the external plug, causing a stoppage of the blood in the vessel between it and the first lateral branch. By being arrested, it forms a conical coagulum, that is to say, in the words of Stilling, "the arrested blood forms a conical mass, whose apex is near the first lateral branch, and whose base is seated on the extremity of the vessel, and is contained within a funnel of blood in partial motion. The larger opening of the funnel, where its walls are sharply cut and very thin, is in the neighborhood of the base of this cone, or just above the extremity of the vessel, whilst its smaller (blind) opening, whose walls are constantly increasing in thickness, until they finally unite, lies near the first lateral branch, in the axis of the vessel or the middle of its cavity." This conical coagulum constitutes an inner plug, which is commonly designated a Thrombus.