Erb’s point [Wilhelm H. Erb] , a landmark of the brachial plexus on the upper trunk, located about 1 inch (2.5 cm) above the clavicle at about the level of the sixth cervical vertebra. The point is the location of an angle between the posterolateral border of the sternocleidomastoid muscle and the clavicle. Electrical stimulation at Erb’s point causes contractions of the biceps, deltoid, and other arm muscles.