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 Medical Corps or 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.
The eight staff corps fall under different organizations throughout the navy. The four medicine-related corps (Medical Corps, Dental Corps, Nurse Corps, and Medical Service Corps) all fall under the Bureau of Medicine and Surgery (BUMED). The Civil Engineer Corps and Supply Corps fall under two of the Navy's systems commands, respectively Naval Facilities Engineering Command and Naval Supply Systems Command. The Judge Advocate General's Corps and Chaplain Corps are directly under the Navy Secretariat.