A teenager who died after suffering a broken neck may have been injured "tumbling" inside a machine during the last day of his summer job, a court heard.

Dean Reynolds, 23, is standing trial accused of the culpable homicide of 17-year-old Michael McLean, who died on August 14, 2015 at Denholm MacNamee's premises in Inverurie, Aberdeenshire.

Mr McLean was found unconscious and bleeding from the ears on the floor of a paint shed in which sat an industrial spooling machine used to raise and lower subsea cables from oil platforms and boats.

His father - who also worked at the firm - frantically tried to give him CPR before he was rushed to Aberdeen Royal Infirmary where he died six days later.

Reynolds' trial was told on Wednesday that a post-mortem examination found that Mr McLean had suffered a broken vertebrae in his neck, which caused a tear in his spinal cord.

That led him to go into cardiac arrest, starving his brain of oxygen and subsequently killing him after a period in intensive care.

Forensic pathologist Dr Matthew Lyall told the sixth day of the trial at the High Court in Aberdeen that a single blow to the head caused during a tumble in the machine could have caused the injuries.

He said: "He had a severe injury that could have produced immediate cardiac arrest, and even if it didn't I would expect it to produce immediate paralysis of all four limbs.

"Even if you were on level ground I would expect someone sustaining that sort of injury to collapse.

"If you combine that with a moving spool you would find it extremely difficult to maintain balance."

Defence QC Iain Duguid asked: "Are you not amazed that if he has been tumbling in a drum that he doesn't have more traumatic head injuries?"

Dr Lyall said: "It just depends how he may have fallen.

"I probably would most of the time expect to have more impacts to the head. He doesn't have a traumatic head injury."

Reynolds, of Keith, Aberdeenshire, denies culpable homicide and an alternative charge under the Health and Safety at Work Act 1974.

He further denies a charge of attempting to pervert the course of justice by discarding two pairs of work boots belonging to him to avoid examination and analysis of them.

The trial continues.