PS. Actually, that above scan indicates a tumor, so it's not a "normal" brain, but it's still in far better shape than Schiavo's was! (and it shows sinuses of course..)
The brain does not have sinuses, the skull does. The anatomical definition of a sinus is a cavity which is completely surrounded by bone. The spaces in the brain are called ventricles through which the cerebral spinal fluid circulates.