failed and Difficult tracheal intubation after direct laryngoscopy is a dreaded complication of general anesthesia as it is associated with serious morbidity and mortality. There are several conventional clinical airway assessment parameters such as the modified Mallampati classification,thyromental and hyomental distance, interincisor distance, neck movementsand neck circumference, which are usually used to predict a difficult airwayand are components of multivariate risk indices. Despite the use of these parameters, the diagnostic accuracy of a preanesthetic airway assessment in predicting difficult intubation is very low. Ultrasound has been evolving as a useful device for airway assessment,and sublingual ultrasound has been used for this purpose.

By an anesthesiologist who is experienced in airway ultrasound, patients will preoperative sonographic assessment . the patient will lie in the ramped up position , with head in the neutral position.The linear probe of the ultrasound machine will be used. Under the patient's chin, The probe of ultrasond will be placed , at different levels, to get the of the submandibular area in transverse view and the upper part of the neck. The transverse view will be used for measuring the the skin to hyoid, tongue volume,and the skin to epiglottis distance. The mid-sagittal view will be used for measuring the distance between epiglottis ,pre-epiglottic space , vocal cords, and the neck fat volume .

Inclusion Criteria:

1. Adult patients above 18 years of age.
2. Both genders
3. Patients scheduled for elective surgery under general anesthesia
4. Obese patients with BMI > 30 kg/m2

Exclusion Criteria:

1. Patients with psychological disorders or those lacking co-operation.
2. Patients with maxillofacial anomalies, restricted neck movements and limited mouth opening.
3. American Society of Anesthesiologists (ASA) physical status class IV
4. Emergency operations

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