Paralysis occurs when you’re unable to make voluntary muscle movements. A nervous system problem causes paralysis. Nerves send signals to your muscles. Those signals make your muscles move. When you’re paralyzed, or have paralysis, you can’t move certain parts of your body.

Paralysis can affect any part of your body. It can be:

• Partial (paresis): You can control some muscles, but not all.
• Complete: You have no control over any muscles.

Paralysis can also be broken down into two types based on the site of injury in your nervous system:

• Flaccid: Your muscles get weak and very loose.
• Spastic: Your muscles tighten, with involuntary jerks and spasms (spasticity).

How common is paralysis?

Approximately 1 in 50 Americans, or 5.4 million people, have some form of paralysis.

Some people experience temporary paralysis and regain partial or full movement over time. For example, Bell’s palsy typically temporarily paralyzes your facial muscles. Palsy is the name for paralysis accompanied by tremors.

Permanent paralysis means you never regain muscle control. The condition is irreversible (can’t be reversed).