Parkinson disease is a disease that affects the part of your brain that controls your movements. You get tremors (shaking), stiff muscles, slow movements, trouble with your balance, and difficulty thinking (dementia).
Your spinal cord is the thick bundle of nerves that runs from your brain down the inside of your spine. The spinal cord is like an electric cable that carries signals back and forth between your brain and body.
Spinal fluid is a liquid that surrounds your brain and spinal cord. Spinal fluid helps cushion your brain if you hit your head or fall. Spinal fluid moves freely around your brain and spinal cord. Eventually, the fluid enters your blood vessels.