Ayeeshia Jane Smith died aged 21 months of a tear to her heart caused by a forceful stamp, prosecutors allege.
It was "feasible" some of the bruising was caused on the potty "if she'd fallen back with enough force", a forensic scientist told a jury at Birmingham Crown Court.
Kathryn Smith, 23, and her partner Matthew Rigby, 22, deny murder.
They have also pleaded not guilty to allowing or causing a child's death and child cruelty.
Smith, of Sandfield Road, Nottingham and Rigby, of Sloan Drive, Nottingham, are accused of murdering Ayeeshia at the flat they shared in Burton-upon-Trent, on 1 May, 2014.
In all, 16 injuries were found on the toddler's body including a historic bleed on the brain, the court heard.
Jurors have already been told the child was known to social services.
Ms Smith and Mr Rigby were "uncooperative" and "hostile" to police at Queen's Hospital in Burton-on-Trent, officers told the court.
The child's mother balled her fists at one officer, while her partner allegedly shouted the police just "wanted an excuse to arrest" her, the court heard.
Det Con Sonia Milligan said: "Parents present all sorts of different emotions, but I have never experienced such hostility as was presented that evening at hospital."
She added:  "[Ms Smith's] initial account of how the injuries were sustained was to do with (falling off) the potty."
The couple were also upset at being told they would not be allowed to go home, as the home in Britannia Drive would need to be searched.
Smith's own mother had earlier told officers her daughter was "concerned" because there was cannabis at the home.
A quantity of the drug was later found inside a Tommee Tippee baby mug in a bedroom.
The trial continues.
A mother accused of murdering her toddler said bruising on the girl's body came from a fall off the potty.