Anatomy, pathophysiology, ultrasound findings and scanning techniques of nerve compression syndromes of median, ulnar and radial nerves. Syndromes discussed are: Pronator and Kiloh-Nevin syndromes as well as carpal tunnel syndrome and palmar cutaneous branch entrapment for median nerve; cubital tunnel and Guyon’s canal syndrome for ulnar nerve; supinator syndrome, Wartenberg’s syndrome and entrapment of posterior antebrachial cutaneous nerve regarding radial nerve. Furthermore entrapment of musculocutaneous nerve as well as medial antebrachial cutaneous nerve will be discussed.

Nerve entrapment syndromes of the upper extremity are associated with structural abnormalities, such as compression, displacement, traction or by an intrinsic abnormality of the nerve. Generally, nerve entrapment syndromes have a typical clinical presentation and findings on physical examination. Electrophysiology can determine the level and type of lesion. Imaging is used to evaluate the cause, severity and etiology of the entrapment. US can identify the abnormalities causing entrapment, such as fibrous bands, ganglia, anomalous muscles and osseous deformities, with the advantage of dynamic assessment under...

No matter which underlying mechanism results in an entrapment syndrome, the reaction of a nerve to external compression has common features. Ischemia due to compression results in fascicular edema. The progression to a more chronic state results in fibrotic changes of the nerve sheath. Sonographic signs reflect these pathophysiological reactions with altered echotexture and shape changes of the nerve. Sonographic signs are an abrupt change in diameter; loss of the normal fascicular pattern of the nerve; swelling or coalescence of fascicles; hypertrophy of the outer...

US is a unique diagnostic modality that allows superb visualization of both large and small peripheral terminal nerve branches of the upper extremity and enables the correct diagnosis of various nerve entrapment syndromes. It is also useful in guiding therapeutic procedures including the neurolysis at the level of nerve entrapment syndromes.

Tagliafico A, Cadoni A, Fisci E, et al. Nerves of the hand beyond the carpal tunnel. Semin Musculoskelet Radiol. 2012 Apr; 16(2):129-136 Peer S, Kovacs P, Harpf C Bodner G. High-resolution sonography of lower extremity peripheral nerves: anatomic correlation and spectrum of disease. J Ultrasound Med 2002; 21:315–322 Bodner G, Buchberger W, Schocke M, et al. Radial nerve palsy associated with humeral shaft fracture: evaluation with US: initial experience. Radiology 2001; 219: 811–816 Gassner EM, Schocke M, Peer S, Schwabegger A, Jascke W, Bodner G....

Tommaso Buzzegoli MD. Department of Radiology, Medical University Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria. E-mail:[email protected]