The brachial plexus is a group of nerves that run from the lower neck through the upper shoulder area. These nerves allow the shoulder, arm, forearm, and hand to move and feel things.
Damage to the brachial plexus nerves can cause muscle and sensation problems that are often associated with pain in the same area. Symptoms may include loss of feeling or sensation in your arm or hand, trouble moving your arm, or a lack of muscle control in the arm, hand, or wrist.
Chad DA. Disorders of nerve roots and plexuses. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta JC. Bradley’s Neurology in Clinical Practice. 6th ed. Philadelphia, PA:Elsevier Saunders; 2012:chap 75.