Spinal Nerves
The spinal nerves are part of the peripheral nervous system. These nerves arise directly from the spinal cord. There are 31 pairs of spinal nerves in the peripheral nervous system. The major function of these nerves is to exchange sensory, motor and autonomic signals between the spinal cord and the body.
Cranial Nerves
The cranial nerves are also the part of the peripheral nervous system. The human body has 12 pairs of cranial nerves. These arise from the brain and spread throughout the head. These are primarily connected with the head, neck and thorax areas. Cranial nerves are numbered in pairs from I to XII. The nerves, I, II and VIII carry only sensory signals to the brain; IV, VI, XI, XII carry motor messages away from the brain; and III, V, VII, IX, X are sensorimotor.