She said the injuries were caused by blunt force. She couldn't comment on the kind of force used to cause the cut on the top of Collier's head. The fractures to his face were probably caused by a different force.
Yesterday one of Mear's former colleagues told the court he saw Mear hitting Collier with a torch and putting his face on the ground.
Constable Brian Newcombe, now stationed in Picton, said Mear got on the bonnet of Collier's car and used his baton to smash a hole in the windscreen. Mr Newcombe said Mear was trying to prevent Collier getting away.
He said he saw Mear strike Collier three times on the back of the head with a police issue torch after he got down from the car.
Mr Newcombe said after he saw Mear pick up Collier's head and push it onto the road he yelled to his fellow officer "that's enough''.
In his opening address for the Crown, solicitor Greg Hollister-Jones described the force used by Mear as "unnecessary, gratuitous and illegal''.
Mr Hollister-Jones said the case rested on the evidence of Mr Newcombe and supporting medical evidence about the injuries suffered by Collier.
In a brief opening statement, Mear's lawyer, Paul Mabey QC, said his client "completely and utterly'' denied the assaults and Mr Newcombe was "a complete liar''.
Under cross-examination by Mabey, Newcombe denied that: "I have no reason to lie. I've told the truth ... I'm not there to protect anyone.''
Collier told the court of "cops jumping over my car whacking my window and my front [wind]screen''.
He said he was kicked in the head and body but didn't know how many times or by whom.
"It felt like heaps...''
Collier said he had been dealt with by the courts on charges of drink driving, dangerous driving, failing to stop and driving while forbidden in relation to the incident.
Other officer involved in his arrest, Constables Phillip Edwards, Francis Martin and Stuart Burgess, have also given evidence.
Mr Edwards said he kicked Collier in the stomach but denied kicking him in the head. He said he had previously been spoken to after kicking someone in the head during another incident.