Fig. 1From: Preoperative X-ray C2C6AR is applicable for prediction of difficult laryngoscopy in patients with cervical spondylosisLateral cervical X-ray film in the neutral positions. HMDn, the distance between the hyoid bone and the tip of the chin in the neutral position; C0C1Dn, the distance between the occipital bone and first cervical vertebra in the neutral position; C1C2Dn, the distance between the first cervical vertebra and the second cervical vertebra in the neutral positionBack to article page