By keeping your head extended somewhat, you’re less likely to obstruct, especially when you’re in deep sleep (when your muscles relax).How does the spinal collar help?
The airway is significantly more collapsible when the neck is flexed, that is, chin towards chest. The spinal collar keeps your chin from being in a position closer to the chest. The idea is to open up the space behind your tongue.
Anyone who knows CPR will tell you the first thing they do is pull your chin up and away from the chest in order to help open up the airway.