Thrombosis has already been discussed under that general heading.

Phlebitis, inflammation of the veins, may follow inflammatory conditions around the vessel, from traumatism, or it may arise from conditions within, by infection from microorganisms circulating in the blood. It may be an acute purulent form in which there is first an infiltration of round cells, then rapidly of pus cells. This condition follows along the vessel, forming abscesses and thrombi. The formation of the latter depends upon the loss of integrity of the intima. The thrombi act as plugs so as to prevent as well as possible the entrance of the invading organisms into the blood, but they may break down and send forth innumerable particles of infecting material.

Chronic phlebitis, or phlebosclerosis, is a condition similar to arteriosclerosis, but is much less common. In it the sclerotic processes predominate, the atheromatous being less marked.

Varicose veins are ones in which dilatation has occurred. This may take place in the neighborhood of a valve, and by rendering it incompetent the blood-pressure is increased. In this way the greater part of a vein may be distended. If the vessel has become longer than normal it will naturally be more tortuous (cirsoid). In this form the various loops may come in contact, and at that point undergoing atrophy of their walls communications will be established; these are known as varices, or varix. Such portions resemble cavernous or erectile tissue.

In the dilated portions thrombi may form or a periphlebitis with the formation of dense connective tissue take place. Phleboliths, thrombi that have undergone calcification, are quite common.

Interference with the venous return seldom leads to as severe results as corresponding lesions in the arteries. This being due to the readiness with which collateral circulation can be established. Varicose veins are most common in the lower extremities. There is generally edema present, and if a skin surface is involved extensive ulcerations may form. These ulcers heal with difficulty on account of the poor nutrition. Another result of venous congestion is the formation of dense connective tissue.

The varicose condition is the result of disease of the vessel wall or of increased venous pressure, brought about by interference with the return flow. This is well seen in the long veins of the lower extremity.

Special names have been given to varicose conditions of certain veins. Dilatation of the spermatic veins is known as varicocele; of the hemorrhoidals, as hemorrhoids.


Inflammation of the lymph-vessels, lymphangitis, is nearly always secondary to bacterial infection. It frequently follows superficial injuries, particularly those received in the making of autopsies. It appears clinically as reddish streaks extending from the point of infection, the result of a perilymphangitis. The inflammation may go so far as to involve distant lymph-nodes, which become swollen, tender, and sometimes suppurate.

The lymph-vessels may become dilated, lymphangiectasis. Is usually due to obstruction by parasites. Is found in elephantiasis.

If there is any defect in the wall of the vessel the lymph may escape into an adjoining cavity or upon the surface of the body. When it enters the abdominal cavity chylous ascites ensues.

Tuberculosis of the lymphatics, particularly when there is tuberculosis of the serous membranes, is common. The vessels appear as grayish lines.

Syphilis commonly involves the lymph-nodes in all its stages.