In the circulatory system, veins (from the Latin vena) are blood vessels that carry blood toward the heart.
Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart.
Veins are less muscular than arteries and are often closer to the skin. There are valves in most veins to prevent backflow.
see Epidural vein
Veins as the source of trigeminal neuralgias (TN) lead to controversies. Only a few studies have specifically dealt with venous implication in neurovascular conflicts (NVC).
The effect of surgically ligating the deep cerebral veins is often thought to be of significant risk. That concern and the paucity of information on surgery of the deep venous system confound surgical decision making when operations involve manipulation of the deep cerebral veins.
Robust experimental studies and limited clinical experience indicate that occlusion of one or several deep cerebral veins is generally safe 1).