 The investigators would like to evaluate 155 patients, who applied to be operated in plastic surgery and ENT clinics, patients between May 2016 and December 2017. The patients will be recruited to study consecutively therefore, there is going to be no randomization. The patients height, age, weight, American Society of Anesthesiology ASA scores will be documented. Additionally, their Mallampati scores, thyromental distance, thyromental height, mouth opening values will be measured with ASIMETO DEPTH GAUGE digitally. Head and neck movement angle measurement will proceed in preoperative evaluation. In the operation room the intubation, determination of C-L and IDS are going to be operated by the anesthesiologist who is in charge of operating room and he or she will not be informed about airway assessments like SPIDS or TMH. The all difficult airway equipment will be readily prepared in advanced. Recorded data will be collected by the assistant researcher. The existing difficult intubation interventions will be determined by using IDS. The relationship between IDS, TMH and SPIDS values will be assessed in the means of predicting difficult airway. 