Final answer:
The cervical plexus is located in the neck and consists of axons from spinal nerves C1-C5. It provides sensory and motor control to the neck, head, and the phrenic nerve, which controls the diaphragm. This plexus is distinct from the brachial plexus, which impacts the arm.
Step-by-step explanation:
The cervical plexus is found within the neck and is composed of axons from the spinal nerves C1 through C5. This plexus branches into nerves that provide sensory and motor control to the posterior neck, head, and the phrenic nerve. This particular systemic nerve is crucial because it innervates the diaphragm, which is essential for breathing and is located at the base of the thoracic cavity. The cervical plexus is not to be confused with the brachial plexus, which is associated with the lower cervical spinal nerves and the first thoracic spinal nerve, and innervates the arms.
Axons from spinal nerves C4 through T1 reorganize to form the brachial plexus. The nerves of the brachial plexus, such as the radial, axillary, ulnar, and median nerves, facilitate movement and sensation in the arm and hand. These nerve plexuses represent a vital reorganization of nerve fibers which allow for complex control over various body regions. The cervical, lumbar, and sacral plexuses all play crucial roles in the peripheral nervous system.