The purpose of the case is to report the clinical value of the ultrasound-guided posterior approach to the brachial plexus in the treatment of phantom limb syndrome after an upper extremity amputation. The author experienced ultrasound guidance as sole technique to localize the brachial plexus for the purpose of placing a catheter for continuous infusion of a local anesthetic in a patient where standard landmark-based nerve stimulation for placement of a continuous perineural block was not possible.