A court heard that a woman "deliberately" burned a child with an iron in a flat.
Coral Ann Chalmers, 22, claims the child was injured after brushing against a cooker that had been used 45 minutes earlier.
However, a paediatric expert concluded the triangular burn sustained by the young boy was most likely to have been caused by an iron.
Chalmers denies causing the boy to suffer severe injury at an address in Dundee by burning his leg with an iron between November 28 and 30, 2019.
Jurors at Dundee Sheriff Court heard how Chalmers brought the child to King's Cross Hospital on November 30 because she was thought he had a cold.
The boy was later taken to Ninewells and told medics the injury "must have" been caused the previous evening.
Chalmers claimed it happened while she was holding the child and trying to reach for a cupboard.
The court heard how Chalmers said the cooker was still hot 45 minutes after using it.
However, a police scene examiner revealed a test found the oven would cool to around 30 degrees, 20 minutes after use.
Dr Jenny Fraser assessed the child and prepared a report that concluded the injury was "non-accidental".
In evidence she said: "Contact would only need to be less than a second for a burn to occur. If it was an accidental burn it would not be symmetrical.
"Overall this injury to the thigh is consistent with an inflicted burn with a household iron."
Fiscal depute Stewart Duncan asked: "Given the shape of the burn, it was suggested that the child had been sat on the cooker, could the injury have come from that?"
Dr Fraser replied: "If a child had been sat on top of it, it would have had a more rounded appearance. You would be more likely to see a burn on the buttocks".
During cross-examination, solicitor Douglas Thomson raised the possibility of the child sustaining the injury by backing into the iron.
However, Dr Fraser said: "The shape of the burn fit with the pattern of the iron.
"I can never be 100 per cent certain but I have difficulty envisioning how the iron would be set up that the child would back into it in that manner."
Earlier, jurors heard from Dr Katherine Lawlor who said she had "misgivings" about Chalmers' version of events after being called out to examine the child at Ninewells Hospital.
It was claimed Chalmers told police the child "never said anything or made a noise" after coming into contact with the cooker and was later sitting on a couch and watching cartoons before being put to bed.
The trial before Sheriff Alastair Carmichael continues.
