Overinflation of laryngeal mask airway cuff increase side effect like hoarseness, vocal cord paralysis, sorethroat. The investigators will study correlation between laryngeal mask airway cuff volume and pressure and physical examination of head and neck.

Overinflation of laryngeal mask airway cuff can induce side effects like hoarseness, vocal cord paralysis, sorethroat. Some study revealed that 60cmH2O of intracuff pressure is maximum pressure which is not increase side effect.

The manufacturer recommends that the cuff is inflated with the minimum volume of air required to provide an effective seal(max volume - size 3, 20 ml; size 4, 30 ml; size 5, 40).

The investigators will measure anatomical structure (neck circumference, neck length, thyroid-mental distance, etc.) which can influence cuff volume and pressure and find correlation between cuff volume and physical figure measured.

Inclusion Criteria:

• Adult (age 19-65)
• American Society of Anesthesiology Classification I-III

Exclusion Criteria:

• cardiovascular disease, cerebrovascular disease, pulmonary disease
• patient who have operation history for airway
• patient who expected difficult intubation
• patient who have risk of aspiration