Final answer:
The four major plexuses of spinal nerves are the Cervical, Brachial, Lumbar, and Sacral plexuses, which innervate various regions from the neck and diaphragm to the arms and legs.
Step-by-step explanation:
The locations of the four major plexuses of spinal nerves are Cervical, Brachial, Lumbar, and Sacral. The cervical plexus is made up of nerves from spinal segments C1 to C5 and innervates the posterior head and neck, as well as the diaphragm. The brachial plexus comprises nerves from spinal segments C4 to T1 and is responsible for innervating the arms. The lumbar plexus originates from all lumbar spinal nerves and provides nerves to the pelvic region and the anterior leg. The sacral plexus arises from spinal nerves L4 to S4 and supplies nerves to the posterior leg.
Among the nerves originating from these plexuses, we have the phrenic nerve from the cervical plexus, the radial, ulnar, and median nerves from the brachial plexus, the femoral nerve from the lumbar plexus, and the sciatic nerve, which includes the tibial and fibular nerves, from the sacral plexus.