Mrs. Bush Fractures Leg in Snow Spill : First Lady: She slams into a tree while coasting on inner tubes with grandchildren at Camp David. Break does not require cast, medication.

Even Arnold Schwarzenegger could not rescue a lady in distress in time to prevent injuries of the sort that come from slamming into a tree.

Thus it was that Barbara Bush had to be carried from the presidential helicopter and whisked across the White House lawn in a wheelchair, with the President at her side.

The 65-year-old First Lady on Sunday suffered a minor break in her left leg from ramming a tree while sliding on inner tubes with her grandchildren and the muscular actor also known as “The Terminator” and “Kindergarten Cop.” The incident occurred at Camp David, the Catoctin Mountain “weekend White House” in western Maryland.

“No damage to the tree,” President Bush commented drily when asked about the accident as he watched a medic and a uniformed Marine carry his wife from the helicopter and transfer her to a wheelchair. First Dog Millie and another family dog, Ranger, sniffed anxiously at their mistress.

Mrs. Bush shook her head when asked if she felt pain.

“It smarts a little,” the President said.

“That’s easy for him to say,” she interjected in mock indignation.

Initial reports said she suffered only scrapes and bruises. But after she was taken by ambulance to the nearest hospital, Washington County Regional, in Hagerstown, Md., X-rays showed a “non-displaced fracture of the left fibula.”

No cast or medication was needed, but Mrs. Bush was told to stay off the leg for three days and use crutches until the fracture mends in an estimated five to six weeks.

Mrs. Bush smiled and joked with reporters and presidential staff members assembled for the First Family’s arrival. The President placed his hand on her shoulder at one point as he walked beside the wheelchair to the White House doorway. Once she was inside, he returned to make a brief statement about Soviet repression of Lithuanian independence and reply to questions about the Baltic and gulf situations.

Anna Maria Perez, the First Lady’s press secretary, said Mrs. Bush was sliding down an icy hill at Camp David on an inflated inner tube with four grandchildren and Schwarzenegger, the bodybuilding movie star who is also chairman of the President’s Council on Physical Fitness. He and his wife, television personality Maria Shriver, were weekend guests.

“She doesn’t know why she didn’t bail out,” Perez said in describing the accident. “She just held on, and the next thing she knew, there was the tree.”

The President had accompanied the First Lady on the slope several times Saturday and again earlier Sunday, but he was not present when the accident occurred.

Dr. Clarence Mohr, a White House physician, examined Mrs. Bush’s bruises and scrapes and dispatched her to the hospital with a corpsman. But Mohr remained with the President, in accordance with established procedure which ensures constant medical attendance.

Although vigorous, Mrs. Bush suffers from a chronic thyroid condition which, she has said, causes double vision and occasional difficulty in balancing.