Osteopathic medicine in the US, is a branch in the medical area.
I've heard of it. What differentiates it from other types of medicine?
Well, they are medical doctors that can practice in all 50 states, and even in Canada regions. 
Oh, ok. Are they sort of like chiropractors?
Osteopathic medicine in the United States
Osteopathic medicine is a branch of the medical profession in the United States. Osteopathic physicians (DOs) can be licensed to practice medicine and surgery in all 50 states and are recognized to varying degrees in 65 other countries.
Frontier physician Andrew Taylor Still founded the profession as a rejection of the prevailing system of medical thought of the 19th century. Still's techniques relied on manipulation of joints and bones, to diagnose and treat illness, and he called his practices "osteopathy". By
Osteopathic medicine
Osteopathic medicine is a branch of the medical profession practiced primarily in the United States, but has also spread to 65 other countries, with universities throughout Europe and Asia, and including Australia, New Zealand and Canada. The Doctor of Osteopathic Medicine (D.O.) degree in the United States is equivalent to the Doctor of Medicine (M.D.) degree and allows medical doctors to practice medicine and surgery in all 50 states. Outside the U.S., a degree in osteopathy is more similar to physical therapy, and exists as