Your brain and spinal cord help control all of your actions and how your body works. It controls things like jumping, breathing, and snapping your fingers. Your brain also controls your senses like smelling, hearing, and thinking.
Your brain is connected to your entire body by nerves. Your muscles have nerves that help them move. Even your skin is connected to your brain by nerves. This is how you feel things. Nerves are very thick and big closer to your brain. The farther away they get from the brain, the smaller and thinner they are.
Because nerves near your skin are so small, it is impossible to have surgery and not cut them. These nerves usually heal with your skin after the surgery. If they do not, you may have a small area on your skin that is numb. The numbness will usually get less and less as time goes on. In extreme cases, a larger nerve may be damaged. This could cause larger areas of numbness or trouble with muscles. Sometimes, the nerve problems or muscle weakness are temporary and go away after a while. Sometimes, the problems are permanent and will stay with you for the rest of your life.