Cervical Plexuses

The cervical plexuses lie deep in the neck on either side. They are formed by the front branches of the first four cervical nerves, and fibers of these plexuses (complex networks) supply the muscles and skin of the neck. In addition, fibers from the third, fourth, and fifth cervical nerves pass into the right and left "phrenic nerves," which conduct motor impulses to the motor fibers of the diaphragm.