Imaging on the painful and compressed nerve: upper extremity.

Compressive neuropathies of the upper extremity are a common cause of pain, weakness, and functional impairment, often resulting from chronic mechanical compression or entrapment of peripheral nerves in anatomical regions such as osteofibrous tunnels, fibrous bands, or muscular pathways. While traditional diagnostic methods, including clinical evaluation and electrophysiological studies, are essential, they are limited in localizing lesions and identifying underlying causes. Advances in ultrasonography (US) and magnetic resonance imaging (MRI), particularly MR neurography and high-resolution 3D volumetric imaging, have significantly improved the evaluation of peripheral nerves by enabling detailed visualization of nerve anatomy, adjacent structures, and muscle denervation patterns. This article reviews the role of these imaging techniques in diagnosing and managing compressive neuropathies affecting the brachial plexus, suprascapular, axillary, median, ulnar, and radial nerves, highlighting key imaging findings such as nerve thickening, signal abnormalities, and muscle changes. The integration of advanced imaging modalities into clinical practice enhances diagnostic accuracy, facilitates surgical planning, and improves treatment outcomes for patients with peripheral nerve compression.