What are some causes of paralysis?

Paralysis means lack of movement of a body part. It could affect one arm, one leg, one side of the face; both legs; or the whole body below the neck. Examples include Bell’s palsy which leads to drooping on one side of the face; a stroke could cause marked weakness in both the arm and leg on the same side of the body; or a spinal cord injury causing lack of movement of both legs or the whole body if the injury is in the neck.