Andrew Huberman· PhD
it actually has all these small what are called fenestrations little holes and canals that run through the skull and through the depth of the skull like little tubes you've got them down here on your mandible you've got them above your lips you have them um on either sides of your nose those are the sinuses the sinuses allow the passage of different fluids through the skull because the skull even though it's bone it's not a dead tissue right in a live person or animal the skull is a very active living tissue indeed all bone is active living tissue and it needs to be nourished with blood it needs to be nourished with cerebral spinal fluid in the case of the skull