State forensic pathologist Dr Christopher Lawrence gave evidence on the fifth day of Joshua Josef Barker's Launceston Supreme Court trial.

Mr Barker, 31, has pleaded not guilty to murdering Dale Watson during an alleged hit-run on Knox Street at Prospect Vale and assaulting Timothy Bumford on York Street in Launceston shortly after.

Dr Lawrence told the court Mr Watson had extensive fracturing at the bottom of his skull and his brain had been severely shaken, causing brain damage.

"The serious injuries are almost exclusively to the head," Dr Lawrence said.

"There was a lot of damage to the right side of the face that extended up to the hairline."

The court heard Mr Watson had a large abrasion and two lacerations on his head, which were consistent with his face hitting a surface like the ground.

Mr Watson's body was found on the road more than 14-metres from the initial impact point on the footpath, the jury was told.

Dr Lawrence said quite a lot of the injuries were caused by Mr Watson's body rolling on the ground, including superficial grazes on his right arm, an abrasion on his left thigh, and bruising.

It was alleged Mr Barker mounted a kerb and hit Mr Watson at a speed between 40km/h and 47km/h.

The autopsy revealed bruises on Mr Watson's right calf and below his right buttock, which Dr Lawrence said were likely to be where the car first hit the alleged victim.

Dr Lawrence said due to there being limited injuries to Mr Watson's torso, it was unlikely his body went under the car.

The court heard Mr Watson was hit to the back of the leg and catapulted, before hitting his head on the ground.

The trial before Justice Robert Pearce was adjourned until Monday, when the jury is expected to hear evidence from a psychiatrist.