Nature has managed the distribution of nerves wonderfully through a single column, the SPINAL CORD (commonly called the back-bone). All the nerves start from the brain and come down to control different organs of the system through the spinal cord.
The spinal cord is made up of small bones (the digits) that fit into one another. At the end of each digit, some nerves come out to control organs in the adjoining area. The nerves that come out at the base of the head spread into the scalp and the face.
They also control the eyes, the ears, the nose, the tongue and the movement of the jaws.
The nerves that come out in the neck, spread in the region of the shoulders and the arms.
Similarly the nerves that come out up to the waist spread out in the back and around the chest and the belly. They control the working of the heart and other important organs in the chest and the belly.
The rest of the nerves that come out at the end of the spinal cord, spread out in the waist, the buttocks and the public region. These nerves also go to the thighs, the feet and the toes. They also cover the genitals.