In the
United States Navy,
commissioned officers are either
line officers or
staff corps officers. Staff corps officers are specialists in career fields that are professions unto themselves, such as
physicians,
lawyers,
civil engineers,
chaplains, and
supply specialists. For example, a doctor can advance to become the commanding officer (CO) of a hospital, a hospital ship, or a medical school or the chief of the
Bureau of Medicine and Surgery, while a supply officer can become the CO of a supply depot or a school or the head of the
Naval Supply Systems Command.