Reference values for nerve ultrasonography in the upper extremity

Introduction: The aims of this study were to identify factors affecting the measurement of nerve cross-sectional area (CSA) and to establish normal reference values for nerve ultrasonography of the upper extremity. Methods: Ninety-seven age-matched, healthy individuals were enrolled. Ultrasonographic tests were performed by tracing nerves from the axilla to the distal arm. CSA was measured at the following locations: median nerve (carpal tunnel inlet, forearm, antecubital fossa, midhumerus); ulnar nerve (wrist, 2 cm proximal to the wrist, forearm, cubital tunnel outlet and inlet, midhumerus); radial nerve (spiral groove, antecubital fossa); and musculocutaneous nerve (proximal humerus). Results: The CSA reference values differed between the measured points along the path of each nerve. Nerve CSA correlated significantly with weight, body mass index, height, and gender; however, the CSA ratio (distal/proximal) did not correlate with demographic factors. Conclusions: The normal reference values may be helpful in diagnosis of pathologies involving these nerves.