In May 1977, a 31-year-old nurse's aide hurt her back raising a window at the Baltimore nursing home where she worked. As a precautionary measure, she had her back X-rayed.

Her physicians told her there was nothing wrong with her back. But there was something else she ought to know -- the X-ray showed a 15 centimeter (6-inch long) surgical clamp inside her abdomen, left there during surgery 5 1/2 years before.

The woman, horrified, immediately underwent surgery and had the clamp removed. She sued for medical malpractice and received $50,000 in a settlement.

If the statute of limitations now in effect for medical malpractice suits in Maryland had applied in her case, though, she couldn't have collected a dime.

The law that did apply to her case said patients could file malpractice suits against doctors within three years of the date an alleged injury was discovered. It didn't matter how long ago the injury had been inflicted.

In 1975 the Maryland legislature enacted a law that requires medical malpractice suits to be filed within five years of the date an injury occurs, except in certain cases involving juveniles.

The new law applies only to persons injured as a result of malpractice after 1975, and so the woman, who discovered she had a surgical clamp in her abdomen 5 1/2 years after surgery, was unaffected by it. She was able to sue.

The physicians and insurance interests that got the statute of limitations changed justified the new limit by saying it put the insurance business on a firmer basis. Without the limit, they said, it would be almost impossible to predict accurately what claims an insurance company would face in the future and set rates to cover those claims.

The new statute of limitations assuredly benefits the insurance companies. Its critics say it will put some future patients, like the Baltimore nurse's aide, in a legal straitjacket, unable to sue for medical malpractice.