Lawyer Saakie Maartens put three probable causes of death to pathologist Dr Celeste de Vaal, who was testifying in the trial of 48-year-old Johannes Christiaan de Jager.
However, De Vaal said all three causes were possible, but unlikely.
“I do not know if all of these are all that reasonable,” she said.
De Jager has pleaded not guilty to murdering Mare in Cape Town in January. He previously explained that he dismembered Mare’s corpse in a state of panic after an accidental fatal fall in a bathroom.
Maartens asked De Vaal if she was familiar with the medical phenomenon commotio cordis.
“It usually has to do with the heart… it’s a very rare occurrence where the impact exactly hits the front of the chest and immediately causes the heart to cease, causing death,” De Vaal replied.
She said this cause of death was usually more specific to young people between the ages of 15 and 30, mostly men, on the sports field.
Maartens asked if she had personally dealt with this cause of death in her four years of post mortem examinations.
“No, it’s too rare,” she replied. The State objected to the line of questioning on the basis that there was nothing wrong with Mare’s heart.
Acting Judge Chuma Cossie said she was unsure where he was going with his questions.
“You are not a doctor. If you are going to be calling a doctor, the court would appreciate it,” she said.
De Vaal offered that it was a probability, but very low on the scale of possibilities.
Maartens raised the possibility of acute neurogenic cardiac arrest as another cause of death, where the heart slowed or stopped and blood could not adequately circulate.
The pathologist said this was usually related to death by suffocation or neck injury and she could not exclude it as a possibility.
Maartens also questioned her on diffuse axonal injury, a type of traumatic brain injury where tissue sheared. De Vaal said a diagnosis of such an injury could only be made under microscope when the person was still alive.
The injury occurred in high velocity situations such as car accidents.
“Once again, it’s possible but very unlikely,” the pathologist concluded.
Maartens asked if the absence of fractures on Mare’s skull excluded the possibility of serious cerebral injury.
She replied that it did not, but that she had not noted any injuries to Mare’s decomposing brain when looking in the skull.
The lawyer said she may have missed something because the brain was not subjected to computerised tomography (CT) scan or a magnetic resonance imaging (MRI) scan.
“The best gold-standard is to remove the top of the skull and look inside. What you see is the best you can get,” she replied.
“I’m not saying there might not have been minor injuries [but] any large haemorrhage would have been picked up.”
She was excused from the stand.
The trial was postponed to December 11.