The Ford Motor Co. agreed yesterday to pay $350,000 to settle a lawsuit alleging that a Falls Church boy's chronic bone condition was triggered by an accident involving design defects in his mother's 1973 Lincoln Continental.

The October 1976 incident prompted one of the first in a wave of suits by consumers nationwide, totaling an estimated 1,500, claiming Ford transmissions manufactured between 1966 and 1979 slipped from "park" into "reverse" and were the result of negligent design.

The settlement, which calls for Ford to pay the amount into a court-supervised fund for 6-year-old Jordan Vance Bartholomew, came shortly before the case was to go to a six-member jury in U.S. District Court in Alexandria.

A Ford spokesman in Washington, Jerry terHorst, said yesterday the company decided over the weekend to settle the case after District Judge Richard L. Williams urged both sides to settle.

"We share in the sympathy for the young boy and are willing to abide by the judge's recommendation," terHorst quoted a prepared company statement as saying.

He said Ford continues to believe there was no defect in the transmission and that the car "did not cause or aggravate" Bartholomew's condition.

The incident occurred on Oct. 22, 1976, as Bartholomew's mother, Constance, was loading groceries into her car at a Falls Church supermarket. The car, its engine idling and its emergency brake on, began to move in reverse, according to an affidavit filed in court by Constance Bartholomew.

The car ran over the woman's left leg and struck several other cars before coming to a stop. Jordan Bartholomew, then about two months old, was in an infant carrier on the front seat. After the car stopped, he was found lying on the transmission hump, Bartholomew's lawyer, Thomas P. Mains Jr., said yesterday.

The infant showed no signs of injury, Mains said, but months later began crying frequently. A physician at the National Institutes of Health eventually diagnosed the child as suffering from a condition in which the body, instead of forming scar tissue, creates new bone growth.

The physician, Dr. Michael Zasloff, linked the cause to the incident involving Bartholomew's Ford-manufactured car, according to documents filed by the plaintiffs.

Jordan Bartholomew today suffers from a stiff neck and back, Mains said. He attends school, but must be cautious to avoid injury, according to the lawyer.

Ford spokesman terHorst said the company believes driver error, not product design, is the cause of any difficulty with the cars. He noted that federal safety officials did not require Ford to recall the vehicles, but permitted the company to issue warning stickers instead.

A spokesman for the Center for Auto Safety, a Washington-based group founded by Ralph Nader, scoffed at the stickers as "a joke" and "a total failure."

The spokesman, Clarence M. Ditlow, maintained there were 26 fatalities involving the park-reverse problem in Ford-manufactured cars after the stickers were issued in May 1980.

Constance Bartholomew, who filed a separate suit against Ford for damages related to her own injuries, won a $50,000 judgment from a Fairfax Circuit Court jury in November 1979. That judgment was later reduced to $16,500 by Circuit Judge Richard J. Jamborsky. The verdict, in that smaller amount, was upheld by the Virginia Supreme Court