Emissary veins passing through the foramen ovale, jugular foramen, foramen lacerum, and hypoglossal canal. Because the emissary veins are valveless, they are an important part in selective brain cooling through bidirectional flow of cooler blood from the evaporating surface of the head. In general, blood flow is from external to internal but the flow can be altered by increased intracranial pressure. A type of emissary vein goes through the sphenoidal emissary foramen inferior to the zygomatic arch with the cavernous sinus on the inside of the skull. This is an important route for spread of infection because cranial nerve VI and the
Varicose veins is returned by the deep veins, the superficial veins, which return only about 10% of the total blood of the legs, can usually be removed or ablated without serious harm. Secondary varicose veins are those developing as collateral pathways, typically after stenosis or occlusion of the deep veins, a common sequel of extensive deep venous thrombosis (DVT). Treatment options are usually support stockings, occasionally sclerotherapy and, rarely, limited surgery. Varicose veins are distinguished from reticular veins (blue veins) and spider veins, which also involve valvular insufficiency, by the size and location of the veins. Many patients who suffer with varicose