During her lunch hour one day in October 1975, Brenda J. Lane was admiring some stuffed animals on display at Stoutenburgh's Pharmacy in Northwest Washington when a 50-pound, 8-foot-high antique mirror fell on her head and knocked her to the floor, unconscious.

Yesterday, Mrs. Lane and her husband Wallace, who brought a lawsuit in D.C. Superior Court as a result of the accident, settled the case for $300,000. Left behind in the courthouse was a tangled legal argument over who was actually responsible for the falling mirror and who should ultimately pay for Mrs. Lane's injuries.

"Nobody would confess to putting the mirror up," said Jacob A. Stein, who represented the Lanes along with attorney Kenneth J. Annis.

The case began simply enough in May 1977 when the Lanes sued Stoutenburghhs for $900,000. Brenda Lane, a secretary at the National Association of Federal Credit Unions at the time of the accident, contended that as a result of head injuries, she suffered dizziness, double vision, and loss of memory and manual dexterity, Annis said. Lane has been unable to work since January 1976, Annis said. Her husband, a carpenter, asked for damages for the loss of his wife's services and companionship, the attorney said.

According to Annis, once the Lanes brought their lawsuit, Stoutenburgh's brought a claim against Coe Construction Inc. of Washington, which it said had remodeled storefront windows and mirrors at the pharmacy in 1961 as general contractor. Coe then brought a claim against a subcontractor, Pittsburgh Plate Glass Co., now known as PPG Industries Inc., which Coe said installed the mirrors, Annis said. PPG Industries said it had no record of any mirror work, Annis said.

Faced with this complicated chain of blame, Jude Norma Johnson decided to leave the question of liability up to a jury. Meanwhile, the Lanes added Coe and PPG Industries to their lawsuit along with Stoutenburgh's and increased their claim to $1.2 million. Annis said. On Thursday, Annis said, agreement was reached with Stoutenburgh's and Coe, and yesterday, just before the trial was scheduled to start before Johnson, PPG Industries joined in the settlement agreement, Annis said.

The settlement agreement ends the case for the Lanes, who get their $300,000 payment. But the mirror dispute is still on in Superior Court.

Stoutenburgh's and Coe are now before Judge Johnson hashing out whether PPG Industries should reimburse them for the money they had to pay to the Lanes. The result of that dispute among the three defendants depends on whom Judge Johnson decides was responsible for the falling mirror. Attorneys for the three could not be reached for comment.