A PATHOLOGIST believes an Ipswich baby found dead in his cot with broken ribs and a bruised face could have been suffocated.
Dr Nathan Milne told Brisbane Coroners Court that the 14-week-old boy would have been screaming in pain from the fractures which he testified were three to six weeks old and the result of significant force.
He said he had ruled out Sudden Infant Death Syndrome as the reason for the boy's death because the SIDS definition could not be used if there was a prior history of violence towards the child.
When asked if he knew the boy would be propped up in bed with pillows and left with a bottle, Dr Milne said he did and labelled it "certainly an unsafe sleeping environment".
He said he had concluded suffocation was the most likely cause of death on September 23, 2009, because of a curved bruising from the child's ear to jaw when added to the rib fracture history.
Dr Milne said the bruise - one of three small injuries to the child's face - which could have been from sustained pressure from a hand that might also have covered the child's face and mouth.
He conceded the bruise also could have occurred from a blow, such as a slap or the child's head hitting an object.
Dr Milne said throwing a child in the air and catching him would not be enough to break the ribs; that there would have to be tight squeezing of the chest after each catch.
"Infant ribs are particularly flexible and they can sustain a significant amount of force before they fracture because they just bend," he said.
"In the presence of unexplained rib fractures, I'd consider that to be inflicted injury without an adequate cause.
"An infant can be fatally smothered without leaving any signs on the body.
"I'm in a position where I don't have a cause of death and, with all the evidence together, I think smothering is ... the most likely cause of death."
Magistrate John Hutton questioned Dr Milne about the pain the baby would have been in with the broken ribs in the lead up to his death - focusing on the likely screaming and potentially frustrated parents.
He questioned whether there was a higher propensity for violence towards a child in such circumstances.
"There's literature out there that children constantly screaming or crying are prone to attacks of violence," Dr Milne said.
Dr Catherine Skellern, a pediatric specialist at the Royal Children's Hospital, said the two bruises and an abrasion on the child's face could not have been self-inflicted.
When asked, Dr Skellern said the facial bruising also could have been consistent with someone gripping the baby's face while trying to force him to suck on a bottle.
The inquest continues.