Sources And Fate Of Arterial and Venous Emboli

Venous Emboli:

Sources Of Venous Emboli;

• 95 % of venous emboli arise from  thrombi in deep veins of the leg ( that are deep calf, popliteal, femoral and iliac veins)
• Rarely venous emboli arise from pelvic veins, inferior vena cava or elsewhere.

Some special types of venous emboli.

1. Saddle embolus.

              It refers to "large snake-like venous embolus that becomes coiled upon itself and impinges on bifurcation of the main pulmonary artery and sits astride the two major subdivisions of the pulmonary artery. such embolus is very dangerous and may cause pulmonary infarction. there is a point to be noted here that lungs also get partial blood supply from bronchial arteries which are branches of aorta hence, complete occlusion of the pulmonary artery is needed to cause pulmonary infarction.

2. Paradoxical Embolus.

         It refers to a venous embolus that enters from right side of the heart to the left side of the heart by passing through an intra-atrial or intra-ventricular defect and gains entry into the arterial system. such embolus is more dangerous than simple venous embolus because it may block larger arteries and may cause massive ischemia, infarction or heart failure.

Arterial Emboli:

Sources of Arterial Emboli.


1. Most commonly from intra-cardial mural thrombi
2. Mural thrombi in aortic aneurysm
3. overlying atherosclerosis plaques in the aorta
4. fragmentation of vegetations on the heart valve.

Fate Of Arterial Emboli:

Arterial emboli follow a shorter course because they travel through the vessels of progressively decreasing diameter, finally lodge in a vessel of smaller diameter than this emboli cause infarction of the organ supplied. for example, if emboli enter into the coronary artery, it causes myocardial infarction, similarly, occlusion of the cerebral artery will cause cerebral infarction.

Other Topic on emboli;

• Emboli and classification
• Arterial and venous embolus
• Fat embolus
• Gas embolus
• Amniotic Fluid embolus