Final answer:
A plexus is a network of interlacing nerve fibers, and the four major nerve plexuses in the human body are the cervical, brachial, lumbar, and sacral plexuses, supplying various parts of the body with nerve signals.
Step-by-step explanation:
A plexus is a network of interlacing nerve fibers without associated cell bodies. In the human body, four major nerve plexuses reorganize axons from spinal nerves to supply nerves to various parts of the body:
- The cervical plexus, which supplies nerves to the posterior head and neck, as well as to the diaphragm.
- The brachial plexus, which supplies nerves to the arm.
- The lumbar plexus, which supplies nerves to the anterior leg.
- The sacral plexus, which supplies nerves to the posterior leg.
These plexuses contain fibers that have sensory functions and others that have motor functions, carrying information to and from the central nervous system.