The surgeon general of the Navy (SGN) is the most senior commissioned officer of the Medical Corps of the United States Navy and is the principal advisor to the United States Secretary of the Navy, Chief of Naval Operations and director of the Defense Health Agency on all health and medical matters pertaining to the United States Navy and United States Marine Corps. As head of the Bureau of Medicine and Surgery, the surgeon general also manages Navy and Marine healthcare policy, administering the services' healthcare and biomedical research facilities as well as the various staff corps of BUMED, including the Medical Corps and an enlisted corps. The surgeon general is also a member of the Office of the Chief of Naval Operations.