Neuropathies of the upper extremity

A spectrum of pathologies can affect peripheral nerves causing peripheral neuropathies. Traditionally, their evaluation relies on clinical history and clinical examination, including electrodiagnostic testing (e.g., nerve conduction studies, electromyography). However, clinical information is often insufficient as it does not provide spatial information regarding the nerves or their surrounding structures, i.e., innervated muscles [1]. Imaging provides important morphological information and thereby often helps in localization and characterization of these pathologies. Imaging using either ultrasound or magnetic resonance imaging (MRI) also can exclude neuropathies by demonstrating normal nerves and muscles. Although morphological assessment is the mainstay of nerve imaging, recent developments such as diffusion-weighted and diffusion tensor MRI may additionally allow functional assessment of nerves in the future [2].