The airway in the upright anaesthetised patient
Tomlin, P.J.; Roberts, J.F.
British Dental Journal 150(11): 312-314
1981
ISSN/ISBN: 0007-0610 PMID: 6940614 Document Number: 175268
A radiological investigation of the airway in seated and supine subjects showed that during anesthesia the soft palate relaxes and hangs by gravity. In the seated subjects the direction of hanging forms a soft seal with the tongue, facilitating total nasal breathing. In the supine subject the soft palate projects into the airway and causes some airway obstruction. During anesthesia the mylohyoid muscle relaxes and the hyoid bone impinges on the airway, causing some subglottic obstruction. Tilting the head backwards causes the hyoid bone to be dragged forward, relieving the obstruction.