Multiple clinical parameters are used to predict difficult airway but incidence of difficult laryngoscopy still ranges between 1.5%-13% probably due to high inter observer differences. Ultrasound is evolving as a useful tool in airway assessment now a days. Ultrasound has several advantages for imaging of the airway - it is safe, quick, repeatable, portable, widely available. 

Patient will be asked to lie supine on a firm surface for ultrasound assessment of anterior neck tissue thickness at the level of hyoid bone, epiglottis and vocal cords using linear probe. Sonographically epiglottis appear as curvilinear, hypoechoic structure with an echogenic pre epiglottic space. Hyoid bone appears as curved echogenic structure with a bright posterior air mucosal interface and hyperechoic pre-epiglottic space. Thyroid cartilage provides the window to view the vocal cords. Vocal cords forms an isosceles triangle with a central tracheal shadow. 

However, not not much research have been done for predicting difficult laryngoscopy using ultrasound. Thus, we are planning to do this study to predict difficult laryngoscopy by using ultrasound and measuring it with clinical parameters.