staff officer who advises the battalion commander on matters pertaining to the health of the battalion. Chief duties include responsibility of managing a battalion aid station (BAS), medical supervision of the battalion PA (physician assistant), performing sick call for members of the battalion, and supervising the medical planning for deployment. The battalion surgeon carries the United States Army rank of captain (O-3), major (O-4), or Navy rank of lieutenant (O-3) or lieutenant commander (O-4). During peace time, a limited amount of Army battalions actually have a physician or battalion surgeon. The exception is aviation, special operations, and stryker brigade support battalions; which routinely have a battalion surgeon. Additionally, US Army maneuver battalions in South Korea maintain their full complement of battalion surgeons. Since physicians are usually in short supply and expensive to employ, most battalions have a PA that performs the duties of "primary care physician" for the members of the battalion. If a battalion is "authorized a physician" during a deployment, then the PROFIS (professional filler system) is used to pull a military physician from a military hospital to deploy with the battalion and serve as the battalion surgeon. A TDA/ MTF (medical treatment facility) physician usually wears a uniform, but they do exactly the same job as a civilian physician. A TDA physician sees military dependants, active duty patients, and retirees. During peace time the PROFIS system is in place, but rarely used. Since the start of Operation Iraqi Freedom and Operation Enduring Freedom (Afghanistan) the PROFIS system has been used routinely. Doctors are "PROFIS" or pulled out of the MTFs in a type of lottery system that factors in the number of deployments the physician has been on, their specialty, and the length of time of the PROFIS assignment. Since most of the physicians chosen to be PROFIS battalion surgeons have been in primary care fields, the Army has had a hard time retaining or recruiting physicians with those specialties. Marine corps battalion aid station Because of the strictly combatant role of the Marine Corps, the Marine Corps does not have organic medical personnel and the Navy supplies medical officers and hospital corpsmen for them. As with the Army, the battalion surgeon is the chief medical officer in a Marine battalion. The battalion surgeon is a staff officer who advises the battalion commander on health and medical matters pertaining to the battalion. A battalion surgeon carries the