Curious  the sphenobasilar joint goes posterior and inferior on inhalation.  Is it the same situation as the IVC during inhalation.  Does it squeeze or "collapse" the vertebral artery in the foramen magnum?  Is that what creates venous return and the opening of the foramen Magnum on inhalation to invite arterial and cerebral spinal fluid supply on exhalation?  All my appreciation, Carri Kaplan