The brachial plexus is a network of nerves that originates in the neck and runs through the shoulder, arm, and hand. It is responsible for the movement and sensation of the upper limb. The brachial plexus is made up of five spinal nerves: C5, C6, C7, C8, and T1. These nerves combine and form three trunks that further divide into several branches that supply the muscles and skin of the upper limb.