After high school, the lucky (or unlucky) ones get into medical school. In Jordan it's six years. The first year is "the general sciences" with chemistry, physics and biology. Years 2 and 3 include medical sciences with no clinical experience. During years 4,5,6 students rotate through different clinical rotations in clinical settings, and they sit for exams at the end of the year. It's during these years that a student decides on the speciality s/he's interested in.
In the US it's a bit different. Students do not go directly into medical school but they have to get a degree first in something like chemistry, biology, economics...etc and they spend as long as it takes to finish these studies before doing the MCAT exams. If they did well in college and scored well on the MCAT, they get an acceptance into medical school.
That's why thousnads of Jordanian high school graduates have joined the AUB to study medicine but those who actually graduated from its medical school are fewer than 50.
After graduation from medical school, these "doctors" are still not allowed to practise medicine in the US, while in Jordan they're allowed to open their private clinics or join the hospital of their choice under the title "general practitioner".
In the US, they have to go through residency. There are dozens of specialities. Residencies last between 3 to 7 years. Residents start as interns, then they progress to more senior residents. Residents in general do the most work and they are supervised by an attending physician (specialist). The most senior residents are almost completely independent and comfortable working without supervision , however they cannot get patients in or out of the hospital or make major decisions without their attending physician's approval, and they need to give him a daily update on the patient and discuss the treatment plan with them.
The residency system is not much different between Jordan and the US, and at the end doctors can practise on their own or choose to do something called "fellowship", or a sub-speciality. For example a doctor who specialized (did residency in internal medicine) can choose to to become an internist or do a sub speciality in lung or heart or kidney disease. A surgeon can choose to stay a general surgeon or specialize in heart surgery and so on.
In general people who decide to do fellowships spend extra years but at the end become the experts in a certain area they truly enjoy doing, and earn more money. In Jordan fellowships have very recently started to emerge but they were nonexistent when I left Jordan in 2004.
That is a very general idea on how it works.
I joined medical school in 1996, finished residency in 2002, did a year of "imtiaz" that was a total waster of time, started residency in internal medicine in 2004, finished residency in 2007, and started the fellowship in infectious diseases last July. I will be done with fellowship in June 2009. Although I currently have my own patients in the clinic that I follow, and I make most decisions on the ill patients I see in the hospital, I am still always under the supervision of a specialist and I can't even leave a note on a patient without his signature on it.
I started in 1996, will be done in 2009 !!
..... 13 years
totally worth it.