Head injuries suffered by the baby boy allegedly beaten to death by an English childminder, Ms Louise Woodward, could have been received days or weeks before the boy arrived at hospital, Middlesex Superior Court in Cambridge, Massachusetts, heard yesterday.
Scans taken while nine-month-old Matthew Eappen was fighting for his life were consistent with a two to three-week old injury which had started bleeding again, a brain surgeon said.
Dr Joseph Medsen also admitted that a blood clot which the defence claims could prove the age of Matthew's brain injuries had not been saved for examination.
During five hours of rigorous cross-examination by the defence lawyer, Mr Barry Scheck, the neurosurgeon said he did not think the injuries could have been caused accidentally. And he ruled out the possibility that the brain damage had been caused by an existing condition which had worsened.
But when questioned by Mr Scheck, he was shown CAT scans and asked: "Let us assume Matthew Eappen suffered a skull fracture two to three weeks prior to admission to the hospital and the swelling went down afterwards. Aren't these consistent with that kind of event?"
The doctor admitted: "Yes, that would be consistent."
But he still said if it had been an old injury he would have detected it by the colour of the blood and he had found nothing to indicate that it was.
Ms Woodward (19), of Elton, near Chester in England, denies beating Matthew's head against a hard surface and shaking him so violently to have caused haemorrhaging behind the eyes. She faces life without parole if convicted.
The defence claim that Matthew's condition in the two days before he was admitted to hospital, where he died five days later, showed all the signs of an earlier head injury. They say that blood clots removed from his brain could have provided vital evidence.
Dr Medsen told Mr Scheck he did not believe the specimen would have revealed an old injury and that he had thought it would have fallen apart before reaching a pathologist.
But Mr Scheck asked: "You could have taken it, put it in a bottle, labelled it and sent it there. You could have done that?"
Dr Medsen admitted: "Yes, we could have done that."
A radiologist who took X-rays of Matthew's skull, which had a 2 1/2-inch fracture, said it was difficult to tell the age of the injury. The condition of the bone around the edges was sharp, indicating a recent injury. Dr Robert Cleveland said: "It could have been the day before the film was done. It could have been days, even weeks earlier."
The defence also claimed to be in possession of notes written by Matthew's mother, Dr Deborah Eappen, on the day he was taken to hospital. They are claimed to show he was lethargic, sleeping for long periods and had been behaving strangely - all signs said to be associated with an existing brain injury.
Earlier Ms Woodward's lawyer, Mr Andrew Good, told the jury: "Louise Woodward will testify in this case. You'll get to know her. She's always been willing to answer questions - everyone's questions - from the start."
Ms Woodward arrived in the United States in June 1996 to spend a year working and taking advantage of cultural and educational opportunities, according to Mr Good.