The diploic veins (Latin: venae diploicae) are large, valveless veins with a thin vascular wall in the diploe between the inner and outer layers of the cranial bones. The diploic veins are connected with the cerebral sinuses by emissary veins.
The main diploic veins that are found on each side of the skull include:
The frontal diploic vein empties the into supraorbital vein and superior sagittal sinus, the anterior temporal diploic vein flows into the sphenoparietal sinus and one of the deep temporal veins. The posterior temporal diploic vein drains into the transverse sinus. The occipital diploic vein is the largest of all, and it empties into the occipital vein or into either transverse sinus or the confluence of sinuses.