Nichol H C, Zuck D
Br J Anaesth. 1983 Feb;55(2):141-4. doi: 10.1093/bja/55.2.141.
The atlanto-occipital distance is the major factor which limits extension of the head on the neck. It varies widely in the population at large. When the posterior tubercle of the atlas is already in contact with the occiput in the neutral position, attempts to extend the head result in anterior bowing of the cervical spine, and forward displacement of the larynx. This may be a cause of difficult laryngoscopy.
寰枕距离是限制头部在颈部伸展的主要因素。在普通人群中，其差异很大。当寰椎后结节在中立位时就已与枕骨接触，试图伸展头部会导致颈椎前凸以及喉部向前移位。这可能是喉镜检查困难的一个原因。
