Fig 3.

Serial dissection of a fresh specimen.

A, Superior topographic view of the right. The brain has been removed and the bridging veins of the temporal pole, in this case a single superficial middle cerebral vein (black arrowhead), have been sectioned close to the brain surface. The superficial middle cerebral vein is attached to the dura mater overlying the lesser sphenoid wing but keeps the appearance of an arachnoid vein. Note the different appearance between the superficial middle cerebral vein and the middle meningeal vessels (white arrowheads), the latter being embedded in the dura mater. The superficial middle cerebral vein terminates in a laterocavernous sinus (black arrows). Note that in this case the laterocavernous sinus shares both arachnoid and dural characteristics being as translucent as the superficial middle cerebral vein but more greatly embedded in the dura matter. The lateral wall of the cavernous sinus becomes a definite dural venous sinus more posteriorly (white arrows) as it drains into the superior petrosal sinus (asterisk). ICA signifies internal carotid artery.

B, The dura mater of the middle cranial fossa and the ridge of the lesser sphenoid wing have been removed to reveal the sphenoid (small black arrows) and parietal (large black arrow) portions of the anterior branch of the middle meningeal veins and the sinus of the lesser sphenoid wing (black arrowheads). The white arrows demonstrate the location of the sphenoparietal canal (of Trolard), whose roof has been removed. The superficial middle cerebral vein (black double arrow) has been kept in situ and no connections are demonstrated with the sinus of the lesser sphenoid wing. The anterior branch of the middle meningeal artery is seen between the two veins that constitute the anterior branch of the middle meningeal veins.

C, The inner bony plate of the frontal and sphenoid bones has been removed to expose diploic vessels. Part of the roof of the orbit has been removed to expose the superior ophthalmic vein (SOV). The diploic vein of the orbital roof (black arrowheads) is followed anteriorly and exits the skull through the supraorbital foramen (not shown here). The diploic vein of the orbital roof connects with a frontal diploic vein (white arrows) that drains into the superior longitudinal sinus. The diploic vein of the greater sphenoid wing (black arrows) drains into the pterygoid plexus extracranially.