Final answer:
The cervical plexus is composed of axons from spinal nerves C1 through C5 and branches into nerves in the posterior neck and head. The brachial plexus is another plexus from the cervical level that gives rise to the nerves of the arms. The radial nerve is a large nerve from the brachial plexus.
Step-by-step explanation:
The cervical plexus is composed of axons from spinal nerves C1 through C5 and branches into nerves in the posterior neck and head, as well as the phrenic nerve, which connects to the diaphragm at the base of the thoracic cavity. The other plexus from the cervical level is the brachial plexus. Spinal nerves C4 through T1 reorganize through this plexus to give rise to the nerves of the arms, as the name brachial suggests. A large nerve from this plexus is the radial nerve from which the axillary nerve branches to go to the armpit region. The radial nerve continues through the arm and is paralleled by the ulnar nerve and the median nerve.