Final answer:
The plexus formed by the anterior rami of C5-C8 and T1 is the brachial plexus, which is responsible for the nerve supply to the arms, including the radial, ulnar, and median nerves.
Step-by-step explanation:
The plexus formed by the anterior rami of C5-C8 and T1 is the brachial plexus. This nerve plexus is associated with the lower cervical spinal nerves and the first thoracic spinal nerve. It is responsible for reorganizing the axons from these spinal nerves to give rise to the nerves that enervate the arms. Significant nerves arising from the brachial plexus include the radial, ulnar, and median nerves. For example, the radial nerve sends motor impulses to muscles of the arm and receives sensory information from the skin of the arm.