KEY POINTS:
The Kahui twins suffered braindamage after their heads were slammed against a hard surface,causing extensive bleeding and bruising, a child abuse expert says.
Dr Patrick Kelly, a specialist paediatrician at Starship hospital in Auckland, yesterday told the High Court trial of the babies' father, Chris Kahui, that he believed the injuries were sustained just moments before Kahui began CPR on one of them.
Kahui denies murdering the 3-month-old boys on June 12, 2006. He says someone else, probably their mother, Macsyna King, inflicted the fatal injuries.
Dr Kelly shed more light on the severity of the twins' injuries, telling jurors that a "violent deceleration" caused bleeding and bruising to both babies' brains.
The key factor in both babies' injuries was the trauma caused when their brains struck their skulls, causing veins to be torn from the brains and extensive bruising.
"The brain could be thought of as floating in a bath, a tight-fitting bath ... it's close up against the skull and is only attached in a limited number of points," he said.
"The skull stops but the brain keeps moving of its own momentum."
He said shaking could have occurred too, but he could not be certain.
Dr Kelly said the injuries suffered by the twins were "very severe, right at the top of the scale" and that anyone who saw the force being applied would immediately know it was inappropriate.
In reply to a question from crown prosecutor Simon Moore, Dr Kelly said the rails of the cot, the floor, wall or even the door of the nursery where they slept were hard enough to cause the babies' head injuries.
The impact would not have caused external bleeding and would have only taken seconds.
Within minutes of this happening, the babies would have shown symptoms of major head injury, he said.
Dr Kelly was read evidence given by the twins' uncle, Stuart King, who told of seeing Cru going purple, flimsy, and his eyes rolling back in his head. That was a "superb" description of what would have happened immediately after an infant suffered a head injury, Dr Kelly said.
Asked if he could pinpoint when the twins lapsed into coma, Dr Kelly said he could not be sure but given baby Cru had not fed for about 20 hours by the time he arrived at Middlemore Hospital, a starting point was about 8.30 or 9 the night before.
"There's something seriously wrong with a baby who hasn't fed for 20 hours."
The crown case against Kahui is expected to end today.
