Doctors have been on television for about as long as there have been televisions and they show no signs of leaving.

Medical shows are critical darlings - most recently with "House, M.D." and "Grey's Anatomy" edging out newer shows for top honors at the Emmys and Screen Actors Guild Awards.

The phenomenon of the TV doctor began in 1952, when CBS and NBC trotted out their first medical dramas: "City Hospital" and "The Doctor," respectively.

No one was expecting these series to be hits, said Robert Thompson, head of Syracuse University's Center for the Study of Popular Television.

"Most genres on television were fully developed on radio and (then) television took them over," said Thompson, adding that medical dramas were conspicuously absent on radio. "Maybe it was really about escapism - they just thought this would be too much of a downer, which makes some degree of sense."

That thinking quickly changed, as these shows attracted viewers and critical success.

"From a series television perspective, this is a perfect genre," Thompson said. "You have automatic life-or-death situations, every single week without having to stretch. Cops, doctors, lawyers and detectives are perfect for series television because you don't have to mess around with credibility to have these life or death situations."

This quickly became apparent, with the addition of more and more medical shows to the prime-time schedule, including "The Medic" in 1954, and later "Dr. Kildare" and "Ben Casey," both in 1961.

"Those shows ('Kildare' and 'Casey') really started that tradition of the doctor as demigod," said Thompson. Not only did they diagnose patients correctly and save them all, but they were exemplary human beings as well. "Both were pretty big hits."

The trend of the heroic doctor continued with "Marcus Welby, M.D." in 1969. By the '70s, dramas like "Medical Center" were re-inventing the medical show as ensemble pieces. A show like "House, M.D." is a bit of a throwback because it is focused on a single doctor. What's different is his insulting bedside manner.

"'House' is an attempt to take the old notion and turn it on its ear," said Thompson. "House is the anti-Marcus Welby. But you can't do Marcus Welby today without a twist like House. It would appear so naive and cheesy."

The early shows had medical consultants, but producers weren't too concerned about having doctors use proper medical jargon.

"Ben Casey and Dr. Kildare were not shouting for lidocaine drips," Thompson chuckled.

With so many series set in the medical field, it seems like TV writers would run out of stories, plots or characters pretty quickly. It took a while, but by the '80s, medical shows were few and far between. Then, in 1994, CBS and NBC faced off with their first medical dramas in years, "Chicago Hope" and "ER." While "Chicago Hope" ran for several seasons, it was "ER," with its mix of emergency room crises and romance, that really captured audiences. Although the cast has turned over, "ER" is still a top draw for NBC.

"ER" is credited with bringing back the genre, with a focus on medical jargon accuracy.

While certain themes seem recycled in show after show, the successful medical drama will often break some sort of new ground.

"I never cease to be amazed at how we never seem to wear out (doctor shows)," Thompson said. "There are no new ways to tell those stories, but by gosh they continue to tell them and some of them are really good. Look at 'Grey's Anatomy' - 'Sex and the City' in a hospital as executed by that group has turned out nicely."

For the foreseeable future, at least, the medical drama is here to stay.