Two teenagers are standing trial in the Supreme Court for the murder of 45-year-old John Bourke, having pleaded not guilty to the offence.

Forensic pathologist Dr Linda Iles gave evidence that Mr Bourke died as a result of facial and head injuries following multiple instances of blunt force.

The court heard Mr Bourke had bleeding under the skull and damage to nerve fibres.

Dr Iles described multiple lacerations and abrasions to Mr Bourke's face and the inside of his lips, which she said were recent injuries caused by blunt force.

The court was also told Mr Bourke sustained deep lacerations to each side of his tongue.

THE TRIAL SO FAR:

DAY ONE: MURDER TRIAL BEGINS

DAY TWO: TEEN CHARGED WITH MURDER WAS DRUNK AND UPSET, COURT HEARS

DAY THREE: SOUNDED LIKE SOMEONE 'WAS BEING ABUSED'

DAY FOUR: TEEN WENT TO WRONG HOME, MURDER TRIAL HEARS

DAY FIVE: ACCUSED TEENS FOUGHT ON NIGHT OF DEATH, JURY TOLD

DAY SIX: DNA OF ACCUSED TEENS FOUND AT HOME, COURT TOLD

DAY SEVEN: 'SUBSTANTIAL' FORCE CAUSED FACIAL INJURIES, MURDER TRIAL JURY HEARS

While it was difficult to quantify force, Dr Iles said a force greater than "mild" had caused these injuries, and the tongue injuries would have required significant force.

The jury heard this opinion took into account Mr Bourke's diagnosis of osteogenesis imperfecta, or 'brittle bone disease'.

The court was told of numerous bruises on Mr Bourke's face and body, including his arms, back, chest and stomach.

Dr Iles said many of these appeared recent, but it was difficult to age bruising.

She gave evidence that Mr Bourke sustained a minimum of 14 blows to cause the injuries he had, including three to the head.

Defence counsel for one of the accused asked Dr Iles if Mr Bourke could have survived if not for his pre-existing conditions, which the court heard included osteoporosis, diabetes and cerebrovascular disease.

"I can't exclude that possibility," she said.

The court heard people with OI were more vulnerable to bleeding under the skull, and this could result from less force than it would in a person without OI.

Such an injury could occur when someone fell and hit their head without breaking their fall, Dr Iles said.

The court heard OI could make a person's skin more fragile and easier to tear, and bruise more easily than the skin of someone without the condition.

Dr Iles said it was fair to characterise Mr Bourke's OI as severe.

Witness statements were read also read to the court.

One witness, who was at a house party with the accused on the night of Mr Bourke's death, wrote that they had spoken to the pair but neither said they had assaulted anyone.

The trial continues.

-Bendigo Advertiser

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