Discs don't slip. Backs don't "go out." And, says Canadian Orthopedic surgeon Dr. Hamilton Hall, don't listen to doctors speaking "Doctor," unless you have a Doctor-English dictionary close at hand.

Patient: Doctor, I have something wrong with my neck.

Doctor (examining): You have cervical spondylosis.

patient (recoiling): Oh my God! Translated into English:

Patient : Doctor, I have something wrong with my neck.

Doctor (examining): You have something wrong with your neck.

Patient (recoiling): Oh my God!"

(Actually, says Hall " 'cervical' refers to the neck, 'spondyl' indicates the spine, and '-osis' means 'disease of' or, loosely, 'something wrong with' . . . "

That little bilingual lesson is from Hall's book, The Back Doctor ($11.95, McGraw-Hill), which is a back-pain syllabus for anybody who's ever had a backache -- or will have one.

"Sooner or later," says Hall, "everybody has a backache." He has calculated, he says, that at any given moment, there are 11 million backs aching in the U.S. and Canada and probably about 100 million cases a year.

Bad backs account for more lost days at work -- almost 100 million -- than anything except the common cold. Around $14 billion a year in medical, insurance, productivity and legal costs, according to a recent series on backs in The Boston Globe.

Hamilton Hall is a surgeon, but he'd much rather not operate. Not on backs, anyway. And he is down on drugs. "They just do not have a uniform effect." (It also has been estimated that as many as half of chronic back patients develop addictions to such drugs as Valium.)

Backs weren't his specialty either: He does, for example, a "real pretty" hip replacement, he says rather wistfully.

But backs were what kept cropping up. Hall develped a little spiel for back patients, explaining how the back works (and doesn't), demystifying the mystery (mystery, he thinks, because you can't see your own back), translating "Doctor."

And, he says, "because I'm a zealot, I'd get all enthusiastic and pound the desk and promise that 'we're going to beat this problem and you and I together are going to ride into the sunset.' . . . It was positively embarrassing and then the next patient would come in and sit down and I'd ask 'what's your problem' and they'd say, 'Doc, I've got this sore back . . .'

"I just couldn't go through all that again, over and over off into the distance." So he got what he thought at the time was a "clever" idea and invited 20 patients to a program on backs in general, invited a physiotherapist to join him and gave a lecture he now says "I sort of made up as I went along."

Hall says he knew he was in trouble when at the end of the lecture the patients said, "Okay, when's the next one?"

That was in 1974. The program grew into the Canadian Back Education program which Hall says is now "the largest multi-center back school in North America." (It has several satellite programs in the U.S.: Lexington, Ky; Miami, Fla; Phoenix, Ariz., and one being set up now in Indianapolis, Ind.)

The program is divided into four, 1 1/2-hour sessions with a follow-up lecture after six months. Lecturers include orthopedists like Hall, physiotherapists and psychiatrists. "What you have to accept about lower back pain is that though there are no such things as purely psychological backaches," says Hall, "there are no such things as totally organic backaches. It's always a combination of the two. And the trick in treating these people is trying to determine how much of which.

"Surgeons," he says, "tend to be much too mechanistic."

But it is also a mistake, he says, to go too far to the other side. (One patient, he recalls, was certain his marriage was causing his had back and was about to leave his wife, even though he claimed to love her dearly. It was just that his back hurt whenever he sat down and started to tell her about his day. It turned out it was his favorite chair, not his wife, that was responsible for the backache. . . .)

Once Hall explains about backs not "going out" (where, he wonders, do they go and when are they coming back?) and explodes the myth of the so-called "slipped" or "disintegrated" disc, he gets to the business of discussing just how much stress a body's poor back can take and what can lighten its load.

Hall divides back complaints into three basic types:

Worn facet joints (the bony projections that link vertebrae). Acute pain almost immediately after "routine" exertion, like picking up a garden tool.

Protruding disc . Slower build-up of pain and long-lasting nagging back pain.

Pinched nerve . Or, as is often the case, an irritated nerve. Pain radiates all the way down the legs, even, sometimes, into the feet.

A backache can be caused by any combinations.

To make it even more complicated, muscles can spasm, exacerbating the attack and referring pain away from its real source, causing panic, confusion, and fear -- which can cause more muscles to spasm. Moreover, the back may bend to compensate for the pain, and that can cause problems with a whole new set of muscles and nerves. For an acute attack, says Hall, there is no substitute for bed rest. And all acute attacks do get better, although they may or may not recur.

The back-education courses allay fears and provide easy, 10-minutes-a-day remedial exercises and a host of tips for everyday living.

To even Hall's astonishment ("all we do is talk,"), the education itself seems to have remedial worth. And indeed, this possibility is being explored in an experiment just beginning with volunteers in Minneapolis. It has been Hall's experience that improvement is cited by 70 percent of participants who have had back problems for 3 or more years, and by 90 percent of those whose bad backs are of a year's duration.

Back problems are discouraging, complicated and confounding even, often, to the doctors. Dr. Hall may not have the definitive answer, but if your back is wayward, his book may help you keep it at home.