Anyone with information on being medically discharged?

My wife is currently going through the process of being medically discharged from the Air Force after getting back from Afghanistan and I was just wondering if anyone with firsthand experience could help give me insight into the process. What benefits will she keep? Does the pay just get calculated by taking your base pay times the percent they attribute to your injuries? Is there a certain time limit you get paid for or is it indefinite? Any other info on what we should be prepared for will be much appreciated. Thanks