A. Dilatation of the veins, Phlebectasis, or Varicosity in its wider sense, is, as is well known, an anomaly of great importance in medicine, whether it be general, occurring as a preponderance of the venous system, or whether it be partial and local. It has attained this importance through certain views regarding its etiological relations, derived from clinical observations: and it has maintained this importance, although the more remote cause to which it has been referred, - the venosity, - notwithstanding all endeavors to elucidate it, has been as yet but little understood in reference to local venous dilatations, and to the formation of true varices. With the view of indicating the necessary points regarding the causes of phlebectasis, we shall first treat of its anatomical relations.

The Form of the Phlebectasis especially belongs to the domain of anatomico-pathological inquiry. Two principal forms may be distinguished.

1. The dilatation of the vein may be uniform and cylindrical, the distended vessel running in a straight line; its coats are either attenuated or not of a thickness corresponding to the calibre; or, on the other hand, they may be visibly hypertrophied and thickened.

2. The dilatation may be irregular, attacking the vein merely at certain spots, or at all events very much preponderating at them. It then includes varicosity, or varicose dilatation of the veins, in the stricter signification of the term.

The venous coats, if not absolutely are relatively thin in proportion to the calibre of the vessel, but after this condition has existed for some time, they very commonly thicken. Varicosity includes two varieties, which merge into one another, and are often simultaneously present in the same vessel.

a. The vein, while it becomes dilated, at the same time becomes elongated, and assumes a winding course, at first forming slightly concave arches; but gradually, as the vein expands on the convex side of the arch, the curve becomes sharper, and the dilatation exhibits itself as a sinuosity on only one side of the vein, while the opposite wall of the vessel is usually tense, but sometimes lying in folds. As this process may be several times repeated on the same side, or as it may alternately occur on either side, the course of the vein resembles the convolutions of the intestine, or, even more closely, those of the vesiculae seminales; indeed, when the vein is sharply bent upon itself, projecting ridges are produced on the interior of the sinuosities - duplicatures of the venous wall, which give to the interior a partitioned structure. We have already (in p. 257) pointed out the derivation of a remarkable degree of dilatation (varicosity) of this kind, both in reference to its winding course and the partitioned nature of its internal structure, from phlebitis, ending in imperfect obliteration.

b. When a strongly marked lateral sinuosity occurs at a circumscribed spot, a true varix is formed. It is a saccular expansion, which either lies with a broad base upon the vein, or is sometimes connected with the vessel by a neck or pedicle; in either case communicating with the interior by a wide or narrow opening. In relation to the construction of the walls of the varix, they are formed of all the coats of the vein; or else we observe the circular fibres separating from one another at certain spots, when the inner coat becomes so fused with the cellular coat, that if a further (secondary) bulging occur the varix assumes a hernial character. The size of the varix ranges from that of a hemp-seed to that of a walnut or a hen's egg, or it may be even larger.

The varix is, as a general rule, originally roundish, but by further irregular dilatation at particular spots, it may assume an irregular, externally lobulated form; while internally it presents a cellular, many partitioned structure. Varices of smaller and more delicate veins not unfrequently present blackberry-like tumors.

The valves exhibit a different relation in phlebectasis. They at first offer such opposition to distension, that they limit and bind down the varix; it is not, however, by any means invariably at the valves that we find these constrictions occurring on varicose veins. The valves increase in size, to a certain degree, with the dilatation of the vein, but after a time they cease to increase, and are no longer capable of closing the enlarged vessel; they then lie, in a state of tension, transversely across the tube of the vein; or they are drawn in an eccentric direction (towards the periphery); or, finally, they may be torn, in which case they float loosely in the vessel, or they' may be almost destroyed, so that we can detect mere traces of them.

If repeated inflammatory attacks have not fixed the varicose veins in their bed of cellular tissue, and made them coalesce with the adjacent structures, they may be often readily detached, and easily raised from it, leaving furrows and cavities, with smooth even walls.

The following are the sequeloe and results of dilatation of the veins, especially of varicosity.

In varicose veins, coagula of blood are occasionally observed in the form of roundish, oval, fusiform, detached plugs, or of cylinders which close the vessel. These are generally again dissolved after a shorter or longer period, and taken up into the mass of the blood; but, as new impediments, they sustain and increase the varicosity. These coagula appear to be very frequently produced in the varicose plexuses of veins, which often occur in the pelvic viscera, new clots being in the act of formation, while the older ones are undergoing solution. They lead-in the manner which has been already described, to the formation of phlebitis.

In large varices, especially such as are connected by a pedicle, we sometimes find stratified coagula of fibrin, as in aneurisms. Such varices are sometimes shut off from the calibre of the vein by a newly formed inner venous coat, investing the last formed stratum of fibrin; or they become separated from the vessel by a prolongation of their pedicle, and a closure of its calibre. In the latter case they degenerate into fibroid capsules.

Varicose veins often, however, open, either externally or into mucous canals and cavities, after they have become imbedded in the tissue of the general investments, or of a mucous membrane which has become extremely attenuated and distended over them; the vein, and the superjacent tissue with which it has coalesced, and which has simultaneously been affected with inflammation, undergoing laceration together.

The varicosity induces stases, which are either transient or persistent, according to circumstances, and are occasionally marked by exacerbations, in the capillary system; and these are followed by various forms of oedema, hypertrophy, increased secretion from the mucous membranes (blennorrhoea), and inflammation, especially of the cellular tissue and the skin, terminating in hypertrophy and sclerosis of the cellular substance, as well as in ulceration.

Moreover, varicose veins are very frequently subject to inflammation. This tendency is most probably based on the stasis which is induced by the varicosity in the vasa vasorum. In accordance with this view, it is generally a chronic affection, whose product is for the most part confined to the cellular coat of the vein and the adjacent cellular tissue, in which it causes hypertrophy and condensation, glues the vein to the neighboring textures, and renders its walls rigid.

The cases, however, in which the inflammation is acute, are sufficiently common. It then deposits a variety of products on the inner surface of the vessel, and its results are either atrophy and obliteration of the varicosity, or acute suppuration.