• The nerve roots of the lower cervical spinal cord split and merge several times before supplying the arm and hand.
• The brachial plexus lies over the first rib and behind the clavicle. It is intimately related to the subclavian/brachial artery and passes between the scalene muscles of the neck.
• The plexus is divided into roots, trunks, divisions, cords and terminal branches. By looking at the anatomical distribution of pain or dysfunction, it is possible to determine the location of a brachial plexus lesion.
• Brachial plexopathy can occur during delivery with or without shoulder dystocia, and from thoracic outlet syndrome.
