• Mary M Chiavaras, Jon A Jacobson, Lisa Billone, Jason Michael Lawton, and Jeffrey Lawton.
• Department of Diagnostic Imaging, McMaster University, Hamilton General Hospital, Hamilton, Ontario, Canada (M.M.C., L.B.); and Departments of Radiology (J.A.J.) and Orthopedic Surgery (J.M.L., J.L.), University of Michigan, Ann Arbor, Michigan USA. chiavamm@mcmaster.ca.
• J Ultrasound Med. 2014 Aug 1; 33 (8): 1475-83.

ObjectivesAbnormalities of the lateral antebrachial cutaneous nerve (LABCN) are associated with antecubital elbow conditions, such as distal biceps brachii tendon tears and traumatic cephalic vein phlebotomy. These can lead to lateral forearm, elbow, and wrist symptoms that can mimic other disease processes. The purpose of this study was to characterize the sonographic appearance of the LABCN using cadaveric dissection and retrospective analysis of sonographic examinations of symptomatic patients with magnetic resonance imaging correlation.MethodsFor the first part of this study, a cadaveric elbow specimen was examined, and sonography was performed after dissection to identify the LABCN. Subsequently, 26 elbows in 13 patients with LABCN abnormalities were identified with sonography and retrospectively evaluated to characterize the appearance of the LABCN in both symptomatic and asymptomatic elbows.ResultsThe symptomatic LABCNs showed fusiform enlargement, increased echogenicity, and loss of the normal fascicular echo texture. The mean cross-sectional area of the symptomatic nerves was 12.0 mm(2) (range, 6.1-17.2 mm(2)), with a maximum thickness of 3.5 mm (range, 2.3-5.9 mm), compared to 3.3 mm(2) (range, 1.9-5.2 mm(2)), with a maximum thickness of 1.3 mm (range, 0.9-2.2 mm), in the contralateral normal elbows.ConclusionsThe close proximity of the LABCN to the distal biceps tendon and the cephalic vein makes it vulnerable to compression and injury in the setting of distal biceps tendon tears and traumatic phlebotomy, which may cause nerve enlargement and increased echogenicity. Awareness of the location and appearance of the LABCN on sonography is important for determining potential causes of lateral elbow and forearm pain.© 2014 by the American Institute of Ultrasound in Medicine.

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