Entrapment neuropathies of the shoulder.

Entrapment neuropathies are a rare but presumably underdiagnosed cause of shoulder pain and painful instability. Radiologists must be aware of the clinical presentations and imaging features of these neuropathies because they may be the first to suggest these diagnoses. In this article, instead of a classical nerve-by-nerve approach, entrapment neuropathies are deciphered according to the clinical situation: which anatomic structures may be involved, how to explore them, which imaging abnormalities can be expected, how to manage differential diagnoses, and which therapeutic options can be considered.