The injuries former WAFL footballer Luke Adams sustained in an alleged one-punch attack were "highly likely to be fatal", a medical expert told a Perth jury today.
Dylan Winter, 20, today exercised his right not to take the witness stand in his own defence as the jury in his District Court grievous bodily harm trial finished hearing evidence.
The only defence witness was Queensland forensic pathologist Professor Anthony Ansford, who gave evidence via video link.
Mr Winter claims he punched Mr Adams in self defence after he stepped in to stop a random drunken fight developing between his close friend and the Swan Districts ruckman on Lake Street in Northbridge early on May 1 last year. Mr Adams, who was felled by the punch and hit his head on the ground, received a fractured skull and life-threatening brain injuries.
Professor Ansford reviewed doctors' reports and Mr Adams' medical notes and imaging and concluded his injuries were a direct result of the fall, not the punch. Professor Ansford said Mr Adams was either too drunk or already unconscious by the punch to brace himself and break the fall.
He said Mr Adams received brain haemorrhaging and swelling and a "complex" fracture that extended from left to right.
Professor Ansford said Mr Adams' situation was consistent with a "contrecoup" injury, in which the damaged area in the brain following a fall is opposite to the point of impact because the momentum forces the brain against the sharp, bony ridges at the front of the skull.
He said Mr Adams' injuries were consistent with a heavy fall on the left side of the back of his head, which resulted in serious damage to his right frontal lobe.
When asked if these these injuries were frequently fatal, Professor Ansford said: "They're highly likely to be fatal."
Professor Ansford also gave evidence about "accelerated falls" in which someone goes to ground without the time to protect themselves, such as putting their hands back or tensing their muscles to break their fall. The jury has heard Mr Adams had a blood alcohol reading of 0.22 per cent after he was taken to hospital.
Professor Ansford said there was no evidence in the material he reviewed of any injury to Mr Adams' face or head that was directly caused by the punch. He conceded that emergency department hospital notes often did not record every injury a patient had.
He said with heavy blows it was not uncommon for victims to suffer facial fractures, with the bones in the faces not as strong as the skull.
Professor Ansford said an intoxicated person was much more likely to suffer an accelerated fall and alcohol widened the blood vessels, meaning it is more likely for the person to bleed from their injury. He accepted that an unconscious person was just at risk as a drunk person of an accelerated fall and the extent of Mr Adams' injuries meant he would have bled profusely regardless of his intoxication.
Professor Ansford said it was a "known medical phenomenon" for a person with these injuries to have no memory of events quite some time before the incident. Mr Adams testified last week he could not remember the punch or encounter with Mr Winter, and his last memory that night was buying vodka at a bottle shop.
Professor Ansford told the court he had personally examined well over 100 people who had died from these injuries, but has reviewed many cases of people who survived.
Yesterday, Mr Winter's video record of interview with police was played to the jury in which the accused man told detectives less than 24 hours after the incident it was a "stupid decision" to back up his mate, who was arguing with Mr Adams, and try to stop a fight that had not started.
He told police Mr Adams threatened to "smash him" and he punched the stranger because he did not want to be hit first, but he knew what he did was wrong.
The trial continues.