It consists of the obstruction of a blood vessel, produced by the formation of a thrombus (blood clot), which can cause an acute myocardial infarction. This condition occurs mainly in the deep venous system, made up of the deep veins, located in the lower extremities.

Thrombosis can be caused by different factors, four being the main ones. First is decreased blood flow velocity, which in turn can be caused by being at rest while lying down, wearing a splint or plaster, dehydration, or a venous condition suffered with anteriority.

Secondly, there are lesions in the vascular wall, caused by wounds, some inflammation or operation, even due to venous alterations caused by age.

Also, the cause of thrombosis is the increase in blood coagulation, which can be caused by medications, which cause the balance between coagulation and the dilution of clots to be altered.

Finally, there is cancer. When a patient suffers from cancer, the chances of suffering from thrombosis are increased by 4 to 20%, with thrombosis sometimes being the cause of death in patients, after having overcome the tumor itself.

On the other hand, the symptoms that originate from thrombosis are pain and swelling in the calf and/or thigh, depending on the location of the clot.

In this sense, thrombosis can be classified according to the location or the level of occlusion that it reaches.

Depending on the location, it can be: thrombosis due to precipitation (white clot), hyaline thrombosis or thrombosis due to coagulation (red clot). The latter represents a high level of severity, since it can cause the death of the structures, ischemia or paralysis in the muscles, if the clot or thrombus is in a vein.

Likewise, depending on the location of the vein, cavernous sinus thrombosis (severe), deep vein thrombosis (medium severity) or superficial thrombophlebitis (mild) may occur.

Due to its level of occlusion, thrombosis can be formed by thrombi or occluding or mural clots, which represent complete and partial obstruction of the vessel, respectively.