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Formation of a blood clot in a vein

Normal blood flow

Cross section of vein, showing blood flowing normally through valve
slide 1 of 3
    
slide 1 of 3, Normal blood flow,

Normally, one-way valves in the veins keep blood flowing to the heart.

Blood clot forming

Blood clot forming
slide 2 of 3
    
slide 2 of 3, Blood clot forming,

A blood clot can form when the valve in a vein does not work properly. If the valve does not open normally, blood cells can collect behind the valve and begin to stick together to form a clot.

Formed blood clot

Cross section of a vein, showing blood clot formed around valve
slide 3 of 3
    
slide 3 of 3, Formed blood clot,

When a blood clot gets large enough, it can stop the flow of blood in the vein.

Current as of: April 9, 2019

Author: Healthwise Staff
E. Gregory Thompson MD - Internal Medicine
Martin J. Gabica MD - Family Medicine
Adam Husney MD - Family Medicine
Jeffrey S. Ginsberg MD - Hematology

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