The 35-year-old police officer and father of a young son was pronounced dead on the scene at Avenue Road on Jan.12, 2011.
Ontario's chief forensic pathologist, Dr. Michael Pollanen, took the stand as the trial for Richard Kachkar — who has pleaded not guilty to first-degree murder and dangerous driving — began its second week.
"It is an unsurvivable injury.... he had serious brain damage," Pollanen said.
"No intervention… would have stopped death in this case."
Pollanen testified that the impact of the plow knocked Russell over and the blade hit him as he fell, leaving him with massive head injuries including a tear to his brain stem.
He added that Russell did not have crushing injuries, suggesting he was not run over by the plow.
Sgt. Jeff Bassingthwaite then took the stand, taking court through a technical analysis of the plow and crime scene and sections of dashboard camera video from Sgt. Russell’s cruiser.
Last week, the jury heard from a paramedic who testified that Kachkar appeared "emotionally disturbed" the morning that Russell was killed.
On Tuesday the trial will shift focus from the crash as the Crown focuses on Kachkar's activities in the days and weeks leading up to the crash, hearing from shelter and employment centre workers from St. Catharines, Ont., — which is where Kachkar was living at the time.