The interscalene block is indicated for procedures on the shoulder and proximal humerus as well as the lateral two thirds of the clavicle. The interscalene block can also be utilized for surgery of the arm or forearm; however, the higher incidence of incomplete block of the inferior trunk with this technique may provide inadequate analgesia in the ulnar distribution. The patient’s positioning and comfort, the surgeon’s preferences, and the duration of surgery may necessitate coadministration of a general anesthetic. An interscalene catheter may be inserted for prolonged postoperative analgesia.