The veins of the brain are valveless, thin-walled structures that drain deoxygenated blood from the brain, meninges, and cranial bones into the venous sinuses. They are divided into superficial cerebral veins, deep cerebral veins, dural venous sinuses, cerebellar veins, and other venous structures, such as diploic and emissary veins. These veins play a critical role in maintaining intracranial circulation and preventing venous congestion.