Most of the bones in Alan Greaves’ face were broken in the fatal attack he suffered as he walked to church last Christmas Eve, a jury heard.
Home Office pathologist Dr Charles Wilson told jurors at Sheffield Crown Court that Mr Greaves’ injuries could have been caused by two weapons.
He said the impact which had caused the head injuries was similar to that usually seen in road traffic collisions, or in someone who had fallen from a high building.
And Dr Neil Stoodley, a consultant neuro-radiologist from Bristol, said that, had Mr Greaves survived, he would have been ‘severely disabled’.
He said Mr Greaves’ injuries were caused using ‘very major degrees of force’ and his brain was ‘completely swollen’.
He said the facial injuries could have been caused by punches or kicks, or by fractures from blows radiating down his head.
Mr Greaves, aged 68, was set upon as he made his way along Greengate Lane, High Green, to play the organ at St Saviour’s Church the night before Christmas.
Jonathan Bowling, 22, of Carwood Way, Pitsmoor, has admitted murder and has been forensically linked to a pick axe handle used to attack Mr Greaves.
But Ashley Foster, also 22, of Wesley Road, High Green, who is on trial for murder, denies the charge.
The prosecution say two weapons were used to attack the husband and grandfather.
Dr Wilson told jurors there were three sites of impact on Mr Greaves’ skull - above his right eye, above his left eye, and on the left hand side of his head above his ear.
Mr Greaves also suffered extensive facial injuries, which Dr Wilson said he suspected were caused by punches and kicks.
Both Mr Greaves’ eye sockets, the bones behind his eye sockets, his cheekbones and his nasal bones were broken, jurors heard.
Dr Wilson said the first head injury was consistent with having been caused by the pick axe handle.
Speaking about the second he said: “Something sharp has cut into the skull and flipped out a piece of bone.”
A bone fragment was found on pavement at the scene of the killing.
He added: “Where I see this kind of injury is when a relatively sharp, heavy object has been used, such as an axe, a machete or a claw hammer.
“Immediately I saw a reconstruction of Mr Greaves’ skull, I didn’t think, ‘This injury has been caused by the same item that has caused the head injury’.
“In my opinion this is caused by something with a relatively sharp edge at an oblique angle, digging in and pushing bits of skull out.”
The trial continues.