Ten anaesthetists assessed the ease of tracheal intubation (time to see the glottis, to intubate the trachea and to ventilate), using the Pentax Airway Scope and Macintosh laryngoscope in a manikin, in three simulated circumstances of restricted laryngoscopy: (1) the patient lying supine on the ground; (2) the patient lying supine on the ground with the head close to a wall; (3) the patient confined to a car driver's seat. For the Pentax Airway Scope, intubation was successful (within 2 min) in all three circumstances. For the Macintosh laryngoscope, intubation was successful in all cases in circumstance (1), eight in circumstance (2), and five in circumstance (3). In circumstances (2) and (3), the Pentax Airway Scope needed significantly shorter time to see the vocal cords (median [95% confidence interval] for difference: 4.5 [0.5-9.5] s in circumstance (2), and 12.5 [7.0-32.5] s in circumstance (3)), shorter time to intubate (median [95% confidence interval] for difference: 21.0 [5.5-38.5] s in circumstance (2), and 40.5 [17.5-64.0] s in circumstance (3)), and shorter time to ventilate the lungs (median [95% confidence interval] for difference: 18. 3 [4.5-36.0] s in circumstance (2), and 47.5 [16.0-84.5] s in circumstance (3)). These results indicate that, in situations where access to the patient's head is restricted, the Pentax Airway Scope is more effective than the Macintosh laryngoscope.