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Updated: June 7, 2025
Minute puncture of arteries such as frequently occur in the hypodermic administration of drugs and in the use of exploring needles, are not attended with any escape of blood, chiefly because of the elastic recoil of the arterial wall; a tiny thrombus of platelets and thrombus forms at the point where the intima is punctured.
We know as an empirical fact that far-seeing tendencies often carry out their purpose, but we know also that they are often defeated by the failure of some contemptibly small process on which success depends. A little thrombus in a statesman's meningeal artery will throw an empire out of gear. Therefore I cannot even hint at any solution of the pragmatic issue.
The needles are made to touch the opposite wall of the sac, and the pulsation of the aneurysm imparts a movement to them which causes them to scarify the inner surface of the sac. White thrombus forms on the rough surface produced, and leads to further coagulation.
In the majority of instances, when there is occasioned serious inconvenience, the outcome is not likely to be favorable, according to Möller. Detachment of a portion of the thrombus, according to Hoare, may result in the lodgment of an embolus in the brain or kidneys. The latter authority also states that muscular atrophy may occur owing to lack of blood supply in some of these cases.
The middle coat contracts and retracts, and the internal, because of its elasticity, curls up in the interior of the vessel, forming a valvular obstruction to the blood-flow. In most cases this results in the formation of a thrombus which occludes the vessel. In some cases the blood-pressure gradually distends the injured segment of the vessel wall and leads to the formation of an aneurysm.
Sometimes the thrombus is mixed a red thrombus being deposited on a white one, it may be in alternate layers. When aseptic, a thrombus may become detached and be carried off in the blood-stream as an embolus; it may become organised; or it may degenerate and undergo calcification.
The development of the collateral circulation which follows upon ligation of the artery at a distance above the sac may be attended with just that amount of return stream which favours the deposit of laminated clot, and consequently the cure of the aneurysm; the return stream may, however, be so forcible as to prevent coagulation of the blood in the sac, or only to allow of the formation of a red thrombus which may in its turn be dispersed so that pulsation in the sac recurs.
Attention must be directed towards the condition with which the phlebitis is associated. Ligation of the vein on the cardiac side of the thrombus with a view to preventing embolism is seldom feasible in the peripheral veins, although, as will be pointed out later, the jugular vein is ligated with this object in cases of phlebitis of the transverse sinus.
#Thrombosis.# The term thrombus is applied to a clot of blood formed in the interior of the heart or of a blood vessel, and the process by which such a clot forms is known as thrombosis. It would appear that slowing or stagnation of the blood-stream, and interference with the integrity of the lining membrane of the vessel wall, are the most important factors determining the formation of the clot.
Sclerostomiasis with attendant arteritis, thrombus formation and subsequent lodgement of emboli in the iliac, femoral, or other arteries, causes sufficient obstruction to prevent free circulation of blood, and the characteristic lameness of thrombosis results. Indirect injury to vessels may occur because of contused wounds and subsequent inflammation of tissues supplied by such vessels.
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