Sonography of entrapment neuropathies in the upper limb (wrist excluded)

The progressive refinement of broadband transducers with frequencies higher than 10 MHz and improved near-field resolution has enhanced the potential of sonography to evaluate a variety of nerve entrapment syndromes occurring in the upper limb, such as suprascapular neuropathy in the area of the spinoglenoid-supraspinous notch, the quadrilateral space syndrome (axillary neuropathy), radial neuropathy in the area of the spiral groove, the supinator syndrome (posterior interosseous neuropathy), the cubital tunnel syndrome (ulnar neuropathy), and the Kiloh-Nevin syndrome (anterior interosseous neuropathy). In these settings, high-resolution sonography can depict changes in the nerve's shape and echotexture and can depict many extrinsic causes of nerve entrapment.