A thrombus forms and by a process of central softening, new channels permeate the thrombus, thus restoring to some extent the function of the vessel.
The occurrence of thrombi is favored and, now and again, a thrombus plugs an artery which supplies an important and even vital part of the brain.
Should the thrombus be on the carotid arteries, hemiplegia may result from cerebral embolism.
As has been shown, arteriosclerosis of the splanchnic vessels not infrequently occurs, and an embolus orthrombus may completely occlude the superior mesenteric artery.
The vessel is then plugged or a thrombus is formed.
If the vessel involved by the thrombus happens to be a mesenteric vessel, then a loop of intestine has its blood supply cut off, and colicky pains result.
There is, however, always danger of a portion of the thrombus becoming detached and producing embolism of the pulmonary artery.
If the obstructed vein is superficial, the seat of the thrombus is indicated by the resistance and sensitiveness of the part.
This is accomplished, according to the researches of Baumgarten,[21] by an outgrowth of endothelium from the intima of the vessel, the thrombusbeing absorbed as the growth of tissue advances.
This simple softening is to be regarded as essentially chemical in character, and begins at the oldest portion of the thrombus and advances toward the periphery.
The primitive thrombus is one which owes its local origin to conditions existing at the place of its formation and attachment.
The production of this form of thrombus is sought for in the treatment of certain aneurisms by direct pressure, the resulting stagnation of blood being followed by a coagulation within the aneurismal sac.
The entire process of which the thrombus is the essential element is designated thrombosis.
Thrombosis with softening and decomposition of the thrombus and embolism, causing local abscesses in the viscera wherever the septic emboli lodge, but without the development of any general infective process.
In the former case, if the thrombus is small and deep-seated, there may be no symptoms to indicate its presence.
The thrombus becomes adherent to the vessel wall within a few hours, after its formation, in the case of the red thrombus, and at once, in the case of the white variety.
Cohnheim claims that the organization of the thrombus may take place solely through the entrance of migratory cells, without any active participation of elements of the vascular wall.
A thrombus is brittle and dry as compared with a clot.
In addition to the palisade worms, one almost constantly finds a parietal thrombus contained in the aneurism.
Under these various conditions the formation of a thrombus is not necessarily associated with the action of bacteria, although in any of them this additional factor may be present.
The bruising of the vessel wall, especially if it is diseased, may result in the formation of a thrombus which occludes the lumen temporarily or even permanently, and in rare cases may lead to gangrene of the limb beyond.
Sometimes thethrombus is mixed--a red thrombus being deposited on a white one, it may be in alternate layers.
The elements of the vessel wall are destroyed by suppuration, and the thrombus in its lumen becomes infected with pyogenic bacteria and undergoes softening.
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 larger the varix the greater is the tendency for a thrombusto spread upwards and to involve the deep veins.
In most cases this results in the formation of a thrombuswhich occludes the vessel.
White thrombus forms on the rough surface produced, and leads to further coagulation.
If the thrombus be practically limited to the jugular fossa the vein may be ligatured above the common facial; if not, as low down the neck as possible.
The chief arguments raised against ligature of the jugular vein are: (1) That it favours extension of the thrombus along the veins communicating with it, especially along the inferior petrosal and condyloid veins, which enter the jugular bulb.
If such cases could be operated on in the earliest stage whilst the infective thrombus was still limited, without doubt a higher percentage of recoveries would be obtained.
If there be no bleeding from the sinus (excepting a slight amount from the blood contained within the isolated portion), the thrombus is curetted out and the inner surface of the sinus inspected.
The lumen of the sinus is obliterated above and below the region of the infected thrombus by plugs of ribbon gauze pressed in between the sinus wall and the overlying bone.
Seeing that there are no symptoms, the presumption is that the sinus is occluded on each side of the septicthrombus by a non-infective clot.
If, at the time of operation, it be doubtful whether intracranial suppuration already exists or not, the surgeon should content himself with removing the septic thrombus from the sinus and await further symptoms.
Except when the thrombus is limited to the upper part of the sigmoid sinus, it is undoubtedly wiser to tie the jugular vein than to be content with curetting out the clot after obstructing the sinus above and below by means of gauze plugs.
The thrombus is then curetted out and the dissected portion of the jugular vein cut off as high up as possible.
If the thrombus be limited to the portion above the entrance of the common facial vein, the upper portion of the jugular may be small and collapsed, only becoming full and pulsating below the point at which the facial joins it.
Further, the thrombus may be situated low down towards the jugular bulb, so that if it has not extended very far upwards the exposed portion of the lateral sinus may still be normal in appearance.
The artery is completely occluded by a clot derived from a thrombus in the right auricle.
Death may take place suddenly from asphyxia, from heart failure, or from displacement of a thrombus from one of the veins in the neck.
The sigmoid sinus is then exposed, and after any granulation tissue or pus that may be in the groove has been cleared away, the sinus is opened and the thrombus removed.
But the thrombus which closes the eroded vessel may easily be washed away, so that the hemorrhage often recurs and continues at intervals for several days, thereby greatly increasing the danger to the patient.
In many cases thrombosis of the arteries, and especially of the veins involved in the diseased tissue around an ulcer, has been observed, and in some the thrombus was prolonged in the vessels for a considerable distance from the ulcer.
The intima especially is much altered in its appearance and structure, becoming thick, opaque, grayish or yellowish in color, and having adherent to it a thrombus passing through its characteristic changes.
Oedema of one extremity follows a thrombus in the crural vein.
When from any of the causes mentioned above a thrombus forms in a vein of the portal system in consequence of the extension of the inflammation about it, the case, what importance soever it previously had, now takes on new characters.
It is probable that in most of these cases the thrombus was secondary to the ulcer.
The onset of the inflammation of the vein walls and the puriform degeneration of the thrombus is announced by a chill--a severe rigor, or chilly sensations at least.
He had recently received an inoculation, one of the constant immunizing injections that were necessary on Antar, for there was a small thrombus clinging to the needle puncture on the inner wall of the vessel.
Chronic endarteritis is fruitful in the production of thrombus and atheroma.
This worm produces an arteritis, with atheroma, degeneration, and dilatation of the mesenteric arteries, associated with thrombus and aneurism.
The first will be the full flow of the circulation through an unobstructed channel, the other a forced passage of the fluid between the thrombus and the coats of the artery.
A history like this suggests a strong suspicion of a thrombus in an artery of the hind leg, and this suspicion will be confirmed by the external symptoms exhibited by the animal.
Illustration: Hyaline thrombus of vessel in centre of a punctate hæmorrhage.
The thrombus was stained brown by dissolved pigment.
When phlebitis begins, a thrombus forms because of the destruction of the endothelial coat, and this clot may be absorbed or organized.
An embolus is a loosened part of a thrombus or any other foreign substance, free in the blood stream, such as a drop of fat, an air globule, or a detached particle of tissue from growths in the heart or vessels.
A thrombus forms, the vein wall suppurates, is softened and in part destroyed, and the clot becomes purulent.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "thrombus" in a variety of sentences. We hope that you will now be able to make sentences using this word. Other words: clabber; clot; coagulate; curd
