Defence lawyer Ron Mansfield is finishing up for the day.

Mansfield asks defence pathologist Stephen Cordner if there is no indicative injury, internally or externally, to support the idea Pauline Hanna died by manual (hands) or ligature (belt, rope or similar) strangulation as part of a homicide?

“There is no evidence of a forensic pathology kind to positively support a conclusion that this deceased has been homicidally, manually or ligaturely killed,” Cordner told the court.

That's it for today. Court will resume 10am Friday, with more evidence from the defence pathologist.

The trial is not sitting tomorrow because jurors have other commitments. Mansfield is also in the Court of Appeal tomorrow.

The defence line of questioning now moves on to manual strangulations.

Ron Mansfield asks defence pathologist Stephen Cordner if we'd expect to see clear internal and external injuries?

Yes, says Cordner.

Mansfield: And we might also see other defensive injuries to the victim?

Cordner: Yes.

Mansfield: And no such injuries in this case?

That's right, says the defence pathologist.

Defence pathologist Stephen Cordner tells the court he would expect to see serious injuries inside the neck or other injuries consistent with assault in a ligature strangulation.

“And the injuries aren't there, are they?” asks defence lawyer Ron Mansfield.

“No, they're not,” says Cordner.

Mansfield is on to manual strangulations.

Cordner says they can be achieved just by hands around the neck, or by a choke hold, called a carotid hold by one of the pathologists called by the Crown, Dr Martin Sage.

That is a hold from behind where the assailant applies enough force to compress both the veins and the carotid artery.

(Carotid arteries are the two blood vessels on either side of the neck taking blood to the brain.)

“It's said SAS-style people are taught this sort of thing as an effective way of overwhelming people,” says Cordner.

Such a hold would require a disparity in strength and size, says Cordner.

That sort of hold could result in blood, skin or DNA under the victim's fingernails, Cordner agrees.

He says you'd expect to see visible bruising on the neck as well.

Mansfield says Cordner has talked about trained professionals like in the police or Army using this hold, but is it commonly used by laypeople successfully in a domestic setting?

Justice Graham Lang interjects, and asks if the witness has come across this in his experience.

"No," says Cordner.

"And that's really my point," says Mansfield.

Cordner qualifies that to say he has been involved with occasional deaths when police apprehend someone and it's unclear precisely how the suspect was apprehended.

"I really wouldn't regard myself as an expert in what the SAS do or more highly trained parts of the police force," says Cordner.

Even with training, Cordner says he'd expect in most cases a carotid hold to cause injury.

Defence lawyer Ron Mansfield asks the witness, Stephen Cordner, how many years he's been a pathologist for.

Cordner says 43 years, but he's been retired for five.

Mansfield: Have you ever had yourself a case of a homicidal ligature or manual strangulation resulting in no internal or external injuries?

“Obviously the answer's no,” Cordner says.

The trial heard earlier Hanna did not have any obvious injuries to her neck.

“It doesn't seem to appear in the literature and I haven't had such a case,” the defence pathologist says.

Mansfield is back to the lack of neck injuries.

Cordner said that if the belt was used as a ligature in a strangulation, it would have moved on the neck, causing abrasions, which were not seen on Hanna's neck.

“We find it easy to underestimate the dynamism of these sorts of events,” he says.

The permutations and combinations of two individuals, one trying to kill the other... “vigorous doesn't do it justice”. It would be “chaotic and hard-fought,” he says.

There would not need to be much movement of the leather woven belt to cause some abrasion, says Cordner.

Defence lawyer Ron Mansfield says we know Pauline Hanna was wearing rings, including some with a stone embedded. During a fight, might skin, blood or DNA become lodged in the ring?

Yes, says defence pathology witness Stephen Cordner.

Further, there might be bruising from the ring apparent if she had been in a fight? asks Mansfield.

The witness agrees.

Neither of the above was identified in the post-mortem examinations, Cordner agrees.

Cordner says he wouldn't want people to think we are sort of close to the mainstream of the sort of injuries that accompany homicidal strangulations.

The number and severity and pattern of injuries to Hanna does not allow the conclusion those injuries were the result of an assault, he says.

We've got minor abrasions and other non-specific injuries, the defence pathologist Cordner clarifies.

"It's about five injuries, and in five of the 27 suicides that I looked at from the institute, there were a small number of non-specific injuries in those cases."

"I really want to be clear we're not in the ballpark of assaultive injuries... where any forensic pathologist could conclude assault," Cordner says.

Cordner says again that 70% of cases of homicidal strangulations showed extensive assaultive injuries. In the other 30%, there were obvious reasons why there were not injuries, such as the victims being young or unwell, he said earlier.

Defence lawyer Ron Mansfield asks pathology witness Stephen Cordner about nail clippings taken from Pauline Hanna.

Cordner explains that's a standard process as part of any autopsy examination in these sort of circumstances.

If the victim has managed to scratch an assailant, there might be skin of the assailant under the fingernails, there might also be blood beneath the nails and therefore DNA, he says.

And you're aware there was nothing by way of Philip Polkinghorne's blood, skin or DNA found? Mansfield asks.

"That's my understanding, yes," says Cordner.

Cordner confirms he's aware Hanna wore artificial acrylic nails.

Mansfield says all her nails were present, or in place, with none dislodged, when her body was examined.

Cordner agrees. But to be fair, one was missing from her large toe, and it was later found in the washing machine with some bedding and gym gear, says Mansfield.

If there was a struggle or a fight... is it helpful or unhelpful as far as you're concerned that all of her acrylic nails were in place, the defence lawyer asks.

Cordner says it's common sense that shows there has not been any great disturbance.

In one study, an author studied 20 assailants in ligature or manual strangulation, and 12 of them had injuries, such as scratches to the face or neck as victims fought back, Cordner says.

The trial heard earlier Polkinghorne had a small fresh abrasion on his forehead when police arrived, but no other injuries.

Cordner says he did not see any form of clear defensive injury suggesting she had been embroiled in a struggle. Not did Dr Kesha or Dr Sage – the pathologists who appeared for the Crown, he adds.

Court has resumed.

Defence lawyer Ron Mansfield KC is questioning pathology witness Stephen Cordner on the cluster of bruises on Pauline Hanna's right arm, seen during the autopsy and photographed.

Cordner says what's interesting about the photograph, compared to the one at the scene, is the one at the scene shows lividity in that area of the arm, but the autopsy version does not.

Does their appearance help us, asks Mansfield, with the level of force that might be applied?

Cordner says that if Hanna was grabbed, the question is why there is no corresponding thumb mark on the other side of the arm, or a grab mark on the other arm either.

Mansfield is on to questions about a single bruise on the right side of her head, near the temple region.

Cordner says it could be accidental, but it could also be blunt force trauma resulting from a punch or other blow.

Mansfield confirms this means it's also a "non-specific injury" that doesn't help narrow down the cause of death.

Cordner tells the court the level of force to cause the bruise to the right temple was not the result of somebody wielding a weapon and did not cause the skin to break.

It's a modest bruise. Mansfield clarifies it's 5cm x 2cm.

There seems to have been a bit of biting of the tongue, Cordner says.

There was hemorrhaging at the base of the tongue as well, attributed to a congestion resulting from the blocking of veins.

Mansfield asks if the injuries he's just traversed are consistent with an incomplete hanging.

Cordner agrees.

"There's nothing incompatible in my view with the presence of those injuries and a conclusion of an incomplete hanging."

Defence lawyer Ron Mansfield asks pathologist Stephen Cordner, even if it had occurred in life, whether the injury is non-specific and does not help prove if it's a manual or ligature strangulation or a partial hanging?

Cordner raises the point that if it was a forceful or violent grip, why was there no mark all the way around the arm? He also says she had a level of alcohol in her blood when she died, and someone could have gripped her to steady her.

“I don't think that constellation of bruises on its own constitutes or justifies a thought that it is assaultive in nature.”

Mansfield has produced the scene photo as an exhibit. It apparently shows no bruising on Pauline Hanna's arm after her death.

To recap – the Crown has suggested they showed bruises in the shape of a grip mark on her arm.

We are taking the afternoon break. Court will resume shortly.

Defence lawyer Ron Mansfield says there was also an abrasion on Pauline Hanna's back.

Defence witness, pathologist Stephen Cordner, says it was not bleeding and there's no bruising, so it's in the same category – superficial – as the nose injury.

“So another non-specific injury that takes us nowhere?” asks Mansfield.

“That's right,” says Cordner.

Mansfield is now referring to the cluster of four contusions – bruises – on her right arm.

“The thing that immediately comes to mind is it looks like a grip,” says Cordner.

He says doctors cannot tell the difference between a bruise that happened 10 minutes ago or a day ago. But they do eventually go yellow, about 18 hours at least after the bruise was inflicted.

“So we don't know when those bruises got there.”

However, there is a photo of the scene showing there are no bruises on her right arm, says Cordner.

Mansfield is producing the surprise photo for the judge.

This is the first the trial has heard of a police photo taken after death that does not show the bruises on her right arm.

Cordner says this is the only photo of the back of the right arm at the scene, and he can't see any of the bruising observed in the same area during the autopsy.

The prosecution is checking something with Mansfield.

His questions resume. He asks how bruising of that kind might occur after death.

Cordner says one reason could be that there was already bruising, but it hadn't appeared yet, because the bleeding from the small injured area under the skin emerged superficially. That's a phenomenon that can continue to occur after death, he explains.

It also does raise the possibility that the bruising could be caused by the movement of the body after death, he says.

"I think it could happen after death, I don't know that it happened after death."

Defence witness, pathologist Stephen Cordner, as an aside is talking about the phrase “consistent with”, explaining it links two things on the level of them being possible.

Martin Sage, a Crown pathology witness, earlier told the trial he did not like the phrase. Cordner doesn't either.

What should he say instead? asks defence lawyer Ron Mansfield.

“You're the master of the words,” says Cordner.

Justice Graham Lang says “a possible explanation” might be better.

To illustrate this point, the petechiae (blood spotting) and facial congestion are consistent with partial-suspension hanging.

But they also can be consistent with death by homicidal strangulation.

Mansfield then refers to an injury on Pauline Hanna's upper-right eyelid.

Cordner says both injuries showed tiny ecchymosis (another word for bruise).

This is another manifestation of the petechiaeal haemorrhages which the jury heard earlier were caused by blood being unable to return from the head, because the veins in the neck are blocked.

There were also a couple of abrasions on the nose, Cordner says.

They do not show evidence of bleeding, he says.

And the pathologist did not describe any bruising or a bleeding nose. So in a medical sense, they are trivial injuries, he says.

But if it's the case there is no bruising, those injuries could have been caused after death.

"Bruising is the hallmark of a vital sort of injury, or bleeding is [also] a vital sign."

The injuries on the nose could have been caused after death, Cordner agrees.