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 foams. Foams may allow more veins to be treated per session with comparable efficacy. Their use in contrast to liquid sclerosant is still somewhat controversial. Sclerotherapy has been used in the treatment of varicose veins for over 150 years. Sclerotherapy is often used for telangiectasias (spider veins) and varicose veins that persist or recur after vein stripping. Sclerotherapy can also be performed using foamed sclerosants under ultrasound guidance to treat larger varicose veins, including the great saphenous and small saphenous veins. A 1996 study reported a 76% success rate at 24 months in treating saphenofemoral junction and great saphenous vein