While every Service branch is afforded care by Military physicians, the physicians who provide that care are drawn from one of three Service branches and their associated Reserve and National Guard components: the Army, Navy and Air Force.
Furthermore, Navy physicians serve the Marine Corps as well as the Navy, and members of the Coast Guard also rely on physicians from the U.S. Public Health Service.
Each branch has its own unique qualities, while Reserve and Guard options offer a part-time obligation that allows you to continue your civilian practice. There are also some differences in the career paths available for active-duty Services and different Reserve and Guard components.