The brachial plexus.

The brachial plexus arises from the lower cervical and upper thoracic spinal nerve roots. It courses between the anterior and middle scalene muscles and adjacent to the subclavian artery. The brachial plexus may be visualized by both MRI and CT. Symptoms of a brachial plexopathy commonly are nonlocalizing. Traumatic injuries and involvement by tumors probably account for the majority of etiologies responsible for these plexopathies. Inflammatory processes also involve the brachial plexus. This article reviews the anatomy of the brachial plexus from both surgical and radiographic approaches and also addresses the symptomatology of brachial plexopathy underlying it.