A statistic that appeared in an article Thursday on actor Christopher Reeve's injury suggested that 72 percent of all riding accidents occur during the cross-country phase of combined training events. According to the U.S. Combined Training Association, the statistic was derived only from combined training competitions, not all riding activities. (Published 6/3/95)

Actor Christopher Reeve, best known for his role as Superman, is paralyzed and cannot breathe without the help of a respirator after breaking his neck in a riding accident in Culpeper, Va., on Saturday.

Reeve suffered fractures to the top two vertebrae, considered the most serious of cervical injuries, and also damaged his spinal cord, John A. Jane, the University of Virginia neurosurgeon treating Reeve in Charlottesville, revealed yesterday.

Reeve, who is 42 and has enjoyed a prolific screen and stage career, was thrown from his horse and landed on his head during the second of three trial events in an equestrian competition. He was wearing a helmet and a protective vest at the time.

"He has sustained complex fractures to the first and second cervical vertebrae . . .," Jane read from a statement at a news briefing. "Mr. Reeve currently has no movement or spontaneous respiration. He may require surgery to stabilize the upper spine in the near future."

While Jane said it is "premature" to speculate on Reeve's long-term prognosis, medical experts were painting a grim picture. "It is a devastating injury, and yet the person is fully aware of what is happening," said Edward C. Benzel, chief of neurosurgery at the University of New Mexico in Albuquerque. There are seven vertebrae in the neck, and any break in the first four, accompanied by a serious spinal cord injury, will cause severe impairment of breathing and quadriplegia. What was not spelled out in Jane's statement is the extent to which Reeve's spinal cord was disrupted. The spinal cord carries nerve fibers traveling both from the brain to the rest of the body and from the body back to the brain. Those coming from the brain are responsible for voluntary control of muscles. Those traveling toward the brain carry sensation. Cameron B. Huckell, an assistant professor of orthopedic surgery at the Johns Hopkins University medical school, said yesterday that "most people who have a complete disruption of the spinal cord don't even make it to the hospital. Only patients who have been rapidly resuscitated survive the initial event and then have a 60 to 70 percent mortality rate at one week." Lawrence S. Chin, assistant professor of surgery at the University of Maryland School of Medicine in Baltimore, concurs. "If there is absolutely no indication of some type of recovery at 48 hours, the chance that there will be recovery is very, very low," he said. Reeve was injured while riding in the Commonwealth Dressage and Combined Training Association finals at the Commonwealth Park equestrian center in Culpeper. He is considered an able rider and a proponent of equestrian safety and was about to pose for a safety poster sponsored by the U.S. Combined Training Association. While serious injuries among competitive riders are rare, USCTA statistics show that cross-country events like this one generate 72 percent of all riding injuries because they involve jumping over fixed obstacles with speed. "The sport takes a lot of balance and training, but everybody who's ridden has fallen. And people who were watching him felt that he was a good rider," says Anne Mercer, executive director of the association, a 10,000-member national equestrian group based in Leesburg. Reeve had been approaching the third of 18 jumps -- a triple-bar about 3 1/2 feet high -- on the course when his horse, Eastern Express, apparently could not find the right spot to make the jump. The horse abruptly stopped, causing Reeve to "roll up the horse's neck and fall on his head on the other side of the jump," according to Monk Reynolds, the equestrian center's owner. Reynolds said an emergency medical team responded immediately and found Reeve unconscious and not breathing. "They gave him mouth-to-mouth resuscitation and he regained consciousness in the ambulance," he said. Reeve was transported to a Culpeper hospital, and then flown to the University of Virginia Medical Center in Charlottesville. His wife, Dana, and their son, his parents and his ex-girlfriend Gae Exton (the mother of his two other children) have been at his bedside. Born and raised in New York City, where he still resides, Reeve first gained prominence in 1978 when he was tapped to star in the feature film revival of "Superman," which he reprised in three sequels. He has achieved critical success in serious film roles such as "Death Trap," "The Remains of the Day" and "The Bostonians." Most recently he starred in "Speechless," a political comedy. Strikingly handsome at 6 foot 4, Reeve has also had a busy stage career at small but prestigious theaters throughout this country and in London. "His friends from the industry are just devastated," said Scott Henderson, Reeve's agent at the William Morris Agency is Los Angeles. "Chris has such an incredibly strong will that if anyone can make a recovery, he can." Staff writer David Brown and special correspondent Vicky Moon in Charlottesville contributed to this report. CAPTION: Reeve is shown riding at celebrity event in Gladstone, N.J., last year.