Two approaches such as ultrasound (US)-guided and prelocation techniques are possible when the internal jugular vein cannulation is attempted with US. This study is a clinical trial that compares the success rates of both techniques and shows the non-inferiority of the prelocation technique. However, during prelocation technique, rotated screen of the US is used instead of original screen. The angle of rotation is determined by the degree of rotation of US probe where an accelerometer is attached.

The investigator's own developed screen-rotating program is used. An accelerometer is attached on the front surface of the ultrasound (US) probe. The angle of rotation of the probe is delivered to the laptop and becomes the information to adjust the rotating angle of screen. Immediately after induction of general anesthesia, the patient's head is turned slightly, and the table is tilted at 10 degrees. In the US group, the investigators obtain a sonographic view and try a cannulation of the internal jugular vein (IJV). In the prelocation group, a skin marker is made on the anticipated skin puncture site where a perpendicular line that passes over the center of the IJV meets the skin on the rotated US screen. It is recorded "success" when the internal jugular vein is successfully punctured without complications. It is recorded "failure" if the internal jugular vein is not punctured during repeated needle passes. The number of tries and tile to success are recorded. The success and complication rates between two groups are compared.

Inclusion Criteria:

• Patients scheduled for general anesthesia

Exclusion Criteria:

• Refusal of consent
• Patients with cervical spine injuries
• Patients with atlanto-axial instability
• Patients at risk of increased intracranial pressure