Which statement about the dural sinuses best describes their role?

• A. They are spaces within the brain tissue
• B. They are formed by arachnoid trabeculae
• C. They drain CSF into the atrial blood
• D. They are formed by splits in dura mater and collect venous blood and CSF for return to circulation

Answer: (D)

Dural venous sinuses are channels formed by splits between the layers of the dura mater that serve as the brain’s venous drainage system. They collect venous blood from cerebral veins and also reabsorb CSF from the subarachnoid space via arachnoid granulations, returning this fluid to circulation through the venous system and ultimately to the internal jugular veins and the heart. This combined role of handling brain venous blood and CSF reabsorption fits the statement best. The other ideas miss the location, formation, or function: they aren’t spaces within brain tissue, they aren’t formed by arachnoid trabeculae, and CSF returns to circulation via the venous system rather than draining directly into the atrial blood.