What is Naprapathy and why is it such a secret to insurance companies and an unknown option to most patients?

Very little is known about naprapathic medicine in the wider health care world. Why do so many people not know about it's benefits for musculoskeletal pain conditions and the nutrition holistic health care they provide when manual medicine has been shown to provide clear advantages over physical types of therapies for certain conditions? What exactly is naprapthy and how does it relate to chiropractic and osteopathic medicine?