Head and neck anatomy may be important in the development of the BBB. Astrocytes may also be responsible for transporting ions (electrolytes) from the brain to the blood. Blood from the brain and neck flows from: (1) within the cranium via the internal jugular veins, a continuation of the sigmoid sinuses. The right and left external jugular veins drain from the parotid glands, facial muscles, scalp into the subclavian veins. The right and left vertebral veins drain the vertebrae and muscles into the right subclavian vein and into the superior vena cava, into the right atrium of the heart. The lymphatic system drains 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