33 - Brachial Plexopathy

Abstract

The brachial plexus is a complicated anatomic structure formed by the ventral rami of the lower cervical and upper thoracic nerve roots. Different fascicles from these roots intermix widely within the plexus to ultimately form all the nerves of the upper extremity. In cases of suspected brachial plexopathy, nerve conduction studies and electromyography (EMG) often are used to localize the lesion accurately and to assess its severity. Detailed knowledge of the anatomy of the upper extremity roots, plexus, and peripheral nerves is required. Extensive bilateral studies, with emphasis on the sensory conduction studies and needle EMG, are frequently needed to localize the lesion. Proper localization is key, not only to exclude a disorder of the nerve roots, which may closely resemble brachial plexopathy clinically, but also to suggest possible etiologies, as certain disorders preferentially affect different parts of the brachial plexus. In addition, assessing the severity is important, especially in cases of trauma, where the results often help decide whether surgery should be considered. Since much of the brachial plexus is located under and below the clavicle, these areas are either inaccessible or barely accessible to neuromuscular ultrasound evaluation. Nevertheless, ultrasound of the brachial plexus offers some unique advantages in the recognition of certain disorders.