To review the imaging features of lower limb entrapment neuropathies.

Peripheral neuropathies are an important cause of pain and functional impairment [1–3]. They can be categorised into non-compressive or compressive aetiology. Peripheral nerve entrapment occurs at specific locations as the nerve passes through a fibro-osseous tunnel or an opening in a fibrous or muscular structure [4–6]. Historically the diagnosis was obtained from clinical history, physical examination and electrophysiological evaluation [7,8]. The symptomology of patient presentation and anatomy of peripheral nerves can vary markedly and therefore the clinical presentation can be ambiguous [9]. Magnetic resonance imaging...

Imaging features Abnormal features of peripheral nerves include increased signal on fluid sensitive imaging and increased cross-sectional area of the nerve. Denervation muscle oedema is an important secondary feature of entrapment neuropathies [11]. An additional technique which is increasingly investigated in MR neurography is diffusion tensor imaging (DTI) [12]. This technique allows accurate visualisation of nerves by means of their fractional anisotropy (FA) and microstructural properties [12,13]. Pathologic conditions of peripheral nerves lead to decreased FA values [12]. Features of high-resolution ultrasound such as increased...

Lower limb peripheral entrapment neuropathies are underdiagnosed in patients due to their ambiguous clinical presentations. Familiarity with anatomy of peripheral nerves is critical for accurate imaging interpretation. Imaging has a critical role in diagnosis.

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