The ethics committee will approved the study and informed consent is obtained. Patients with contraindications for regional anaesthesia will be excluded from the study. 150 patients will be included The arm is placed above and beside the head for scanning (abduction 90 degrees at the shoulder and 90 degrees flexion at the elbow with external rotation) Ultrasound is performed with a 12-18 MHz (Mega-Herz) linear probe (BK medical). The frequency is set to 18 MHz and the depth to 3 cm and adjusted to 1 cm below the brachial artery .