Blowing out with lips and nostrils closed, causing the ears to pop – such as we might do as an aeroplane descends from a height. We do this to drive air into the middle ear, in order to relieve the increasing cabin pressure that is bearing down upon the outside of the eardrums. If performed more vigorously, against a closed larynx (voice-box), a Valsalva manoeuvre will impede the return of blood to the heart, in the veins. The veins engorge and this back pressure is transmitted into the head and the The individual bones that comprise the spinal column are made up of a weight-bearing “body” and other components whi... and, in turn, this pressure is transferred into the This clear, water-like fluid forms, for the most part, within the brain, more specifically inside the ventricles of the ... channels. Coughing, sneezing, laughing, shouting or bending over are examples of every-day actions which are accompanied by brief periods during which we involuntarily squeeze air out of our lungs with the voice-box closed.