AIr Passage Through the Hypopharynx in Unconscious Patients in the Prone Position

SUMMARY The air passage through the hypopharynx was studied radiographically in nine anaesthetised and curarised patients and in eight conscious subjects in the prone position, with the head placed either in the normal position or with maximal extension in the atlanto‐occipital joint. In six of the unconscious and five of the Conscious individuals, the hypopharynx was obstructed (the sagittal diameter at the second cervical vertebra was zero) when the head was in the normal position. With maximal extension of the head in the atlanto‐occipital joint, the air passage through the hypopharynx was found to be unobstructed in all the individuals studied.