Radiological findings of various nerve entrapment syndromes of the upper limb are described.

Peripheral nerves of the upper limb can become entrapped at various points during their anatomical course. There are multiple imaging options, especially ultrasound and magnetic resonance imaging (MRI), that offer information about the cause and location of nerve entrapment, which in turn helps guide treatment [1]. Ultrasound is an effective imaging modality for entrapment syndromes as it is cheap, fast, has high spatial resolution, and allows a dynamic search for pathology [2, 3, 4]. The drawbacks of ultrasound are its small field of view and...

On ultrasound, nerves are more echogenic than muscles and less echogenic than tendons [3, 4]. Along a nerve’s short axis, hyperechoic connective tissue surrounds hypoechoic fascicles, giving a honeycomb appearance [4]. When entrapped, the nerve enlarges proximally to the pathology and becomes thickened and hypoechoic. There may be an ultrasonographic Tinel’s sign, i.e. paraesthesia caused by the transducer compressing the nerve. Neuropathic muscular changes may not be evident acutely; increasing muscle echogenicity may be seen within the first two weeks, with atrophy over the longer...

This poster briefly describes the various upper limb nerves and illustrates common sites and causes of impingement, as well as the typical patterns of denervation oedema. Knowledge of this helps the diagnosis and management of patients with unexplained pain and weakness.

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