Cavernous sinus: RULE OF 3

3 Afferent veins: Sphenoparietal sinus (Vault veins), 

                            Supf Middle cerebral Vein (Brain),  

                            Ophthalmic vein (Orbit)

3 Efferent Veins: Superior petrosal sinus, Inferior Petrosal Sinus, Communicating vein
to pterygoid plexus

3 Contents; Cranial Nerves (III,IV, V1,V2 & VI)

3 Areas Drain into it: Vault Bones, Brain (Cerebral Hemisphere), Orbit

3 Nerves: Motor(III,IV,VI),Sensory (V1,V2), Sympathetic