venous thrombosis

venous thrombosis.

See phlebothrombosis.

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venous

pertaining to the veins.

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venous dilatation

persistent dilatation of the vein but without necessarily any weakening of the wall or varicosity.

hepatic portal venous system

includes the veins from the alimentary tract, the portal vein, the sinusoids in the liver, the hepatic veins and then the entry into the caudal vena cava.

venous infarct

see venous infarct.

obstructed venous drainage

may be generalized or local; manifested by dilation, local edema.

orbital venous plexus

a plexus for venous drainage from the ophthalmic veins at the apex of the orbit; drains into the cavernous venous sinus within the cranium.

venous return

the flow of blood into the heart from the peripheral vessels.

venous return curves

relate venous return to atrial pressure; the inverse of the Starling relationship; an increase in atrial pressure decreases the venous return.

scleral venous plexus

a ring of small vessels around the corneal limbus which forms a link in the chain of vessels which drain the aqueous humor. Called also canal of Schlemm.

venous sinuses

see venous sinus.

venous system

the bodily system of veins commencing with the venae cavae, thence through the large veins and their tributaries, and immediately subsequent to the capillaries, the venules.

venous thrombosis

the presence of a thrombus in a vein. Originates in phlebitis in most cases. It is a major problem in horses because of the high incidence of jugular phlebitis and periphlebitis as a result of injection of irritating materials. See also caudal vena caval thrombosis.

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Patient discussion about venous thrombosis.

Q. How can I prevent blood clots? I am 45 years old and am supposed to go on a business trip overseas. The flight itself is 12 hours long and then I have to continue traveling by bus. Could this cause me to have blood clots? If so, how can I prevent it?

A. Sitting or laying in one position for a long period of time can increase the risk of developing DVT- deep vein thrombosis. Here are some methods to prevent it:
Exercise your calf and foot muscles regularly:
Every half hour or so, bend and straighten your legs, feet and toes when you are seated.
Press the balls of your feet down hard against the floor or foot-rest every so often. This helps to increase the blood flow in your legs
Take a walk up and down the aisle every hour or so, when the aircraft crew say it is safe to do so.
If you are allowed, get off the plane and walk about if the plane stops for refueling.
Consider buying a leg exerciser for the journey.
Drink plenty of water (to avoid dehydration).
Do not drink too much alcohol. (Alcohol can cause dehydration and immobility.)
Do not take sleeping tablets, which cause immobility.
Consider wearing compression stockings.
Some people at high risk may also be advised to take anticoagulant medication by their Dr.

Q. Are long flights dangerous? I'm flying next week to my vacation, and the flight is going to be rather long (almost 16 hours non-stop). Several years ago, my 75 years-old aunt had blood clot in her lung after a flight of similar length. I also heard that during flight the blood in the legs clots and that it can cause after that problems with the lungs and breathing. Does this mean it's dangerous for me to fly? Should I change my ticket to shorter connection flights?

A. Long flights, especially when seating in crowded cabins without moving the legs for long periods can cause the blood in you legs to clot and after that to move to your lungs and damage them. You may try to move your legs during the flights (like getting up and walking a little etc.) This video has some suggestions:
http://youtube.com/watch?v=_mte4WsVZUk