Inclusion Criteria:  Age:20-65 years Undergoing oro-maxillofacial surgery Opening mouth > 3 cm Denied any systemic disease. American Society of Anesthesiologists (ASA) class:I-III  Exclusion Criteria:  Difficult airway assessed (limited mouth opening, limited neck motion, and thyromental distance < 6cm) Previous head and neck surgery history Upper abnormal airway diagnosed Easily epistaxis Both sides nasal cavities obstruction