US-guided Perineural Injections of the Upper Extremity from the Arm to the Wrist.

US-guided perineural injections are quick, cost effective, and safe for diagnostic evaluation and treatment of multiple upper extremity neuropathies. They are performed to confirm a specific neuropathy before nerve surgery or to relieve nerve pain. Nerves in the upper extremity can be damaged from trauma, entrapped by fibrous bands or scars, or damaged from surgery itself. Surgery is increasingly being performed on nerves to relieve neurogenic pain. The radiologist plays a key role in diagnosing and aiding in the treatment of neurogenic pain by injecting around the nerve in question and recording the immediately elicited a response to the injection. US allows for precise nerve localization and real-time needle guidance to ensure that the local anesthetic or steroid and local anesthetic mixture is injected precisely around a nerve. Accurate perineural injection requires detailed knowledge of nerve anatomy and location. The authors review the anatomy and course of select nerves in the upper extremity with MRI and US correlation, including the axillary, musculocutaneous, lateral antebrachial cutaneous, medial antebrachial cutaneous, radial, ulnar, and median nerves. For each nerve, the authors describe patient positioning, US transducer placement, and needle placement for performing these perineural injections and provide representative case examples. With detailed knowledge of nerve anatomy and US techniques, perineural injections of the upper extremity can be performed safely and effectively for diagnosis and therapy.