The parents of a toddler wept as a court heard their baby boy died from whiplash-type injuries to his spine when his mother's car was in a collision with another vehicle.
That car was driven by former Ulster University student John Fahy (25), from Groagagh Grange in Sligo, who denies careless driving causing the death of 19-month-old Ryan John Cox on the Boa Island Road in Fermanagh on January 14, 2013.
The architectural student, who blames baby Ryan's mother Katriona for the fatal accident, also denies causing her grievously bodily injury through careless driving.
Yesterday Mrs Cox and her husband Peter held hands, comforting one and other, weeping quietly in the public gallery as Fahy's Dungannon Crown Court trial heard that despite six hours of intensive treatment in hospital in Enniskillen, baby Ryan was pronounced dead.
A post-mortem carried out two days later in Belfast revealed the cause of the toddler's death was swelling and bruising of the spinal cord brought on by injuries to the cervical spine in his neck.
Pathologist Charolette Randall, in a statement read to the court, reported that: "This type of spinal injury had probably been caused by an acceleration-deceleration injury to his neck as a result of the impact."
Dr Randall also reported that bruising and abrasions to the right side of Ryan's head may have been caused by him hitting his head off the head rest of his forward-pointing child car seat.
Trial judge Madam Justice McBride and the jury of six men and six women heard that while staff battled to save baby Ryan, his mother was transferred, in a medically induced coma, to Altnagelvin Hospital in Londonderry for treatment.
It was left to baby Ryan's uncle James Cox to formally identify the body of his young nephew.
Earlier the court heard from Donegal artist Heather Cassidy about Fahy's driving just prior to the collision.
Ms Cassidy, driving from her home in Inver, said that normally her route would have taken her through Pettigo, but, ironically, that road was closed due to an accident. She said as she drove her "heavy" VW Transporter van through Belleek village she noticed a silver-coloured Renault Megane behind her.
The car, driven by Fahy, remained behind her until outside the border village, when she indicated left, letting him know it was safe for him to overtake her, which he did.
The next time she saw the car it had been involved in the collision with Mrs Cox's Peugeot vehicle.
A series of police-shot videos, showing the Boa Island Road shortly after the accident, and later when the roadway was cleared of all debris, was played to the court.
The four videos, two before the debris was cleared and two after, depicted the approach from both Fahy's and Mrs Cox's point of view, to the point of impact near the entrance to Castle Caldwell Forest Park.
The trial continues on Monday.