Two approaches are possible when the first finder needle attempt of the internal jugular vein cannulation fails; the needle can be turned slightly laterally or the puncture point can be moved slightly medially. This study is an ultrasonographic stimulation study to evaluate the success rate of turning the needle laterally and moving the puncture point medially, and to determine the proper angle or distance for the second try of internal jugular vein cannulation.

Immediately after induction of general anesthesia, the patient's head is turned slightly, and the table is tilted at 10 degrees, and the puncture point estimated by the anatomical landmarks are marked on the patient's skin. The investigators obtain a sonographic view at the estimated puncture point. It is recorded "success" when the internal jugular vein is visualized on the ultrasonography, and the estimated needle path passes the internal jugular vein. It is recorded "failure" if the internal jugular vein is not visualized on the ultrasonography, and the estimated needle path does not pass the internal jugular vein. After "failure" of the first attempt, the probe is either turned laterally or moved medially until the internal jugular vein is visualized on the ultrasonography, and the estimated needle path passes the internal jugular vein. The angle and distance is recorded. The location of the carotid artery is always marked on the ultrasonography for evaluation of complications.

Inclusion Criteria:

• Patients scheduled for general anesthesia

Exclusion Criteria:

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