Bernard Watt was 28 when he was shot dead in Ardoyne in February 1971.
Soldiers told the new inquest into his killing on Monday that they shot him as he was about to throw a bomb.
But acting state pathologist Prof Jack Crane told the inquest on Tuesday that the injuries sustained by Mr Watt did not support the soldiers' claims.
One soldier had said that Mr Watt dropped a bomb he was holding when he was shot, and it had exploded and "blew him down the street".
Prof Crane said there was no evidence that Mr Watt had been thrown in to the air by an exploding device.
Mr Watt's family disputes the soldiers' version of events and his widow told the inquest he had no links to paramilitaries.
The new inquest into Mr Watt's killing began on Monday, and was ordered in 2012 by the attorney general, who asked for a number of controversial Troubles killings by the security forces to be re-examined.
An initial inquest held in July 1971 resulted in an open verdict.
In February, the Ministry of Defence defended a Parachute Regiment Facebook appeal asking former soldiers for information about Mr Watt's killing.

Following two recounts, AM Byron Davies gained the seat with 15,862 votes - a majority of just 27.
Labour's Liz Evans received 15,835.
Political expert Richard Wyn Jones, from Cardiff University, told BBC Wales it was "a bitter blow" for Labour who had held the constituency for nearly 100 years. The win has taken the tally of Tory-held seats in Wales to 11.
"I'm absolutely delighted that the people of Gower have put their faith in me," Byron Davies said.
Meanwhile, Stephen Kinnock, the son of former Labour leader Neil, has become an MP after Labour held on to Aberavon.
Elsewhere, the party also held Neath, Llanelli and Swansea East.
Conservative Stephen Crabb retained his Preseli Pembrokeshire seat where he has been a MP since 2005.
Labour's Geraint Davies kept Swansea West and Plaid Cymru's Jonathan Edwards held Carmarthen East. Tory Simon Hart held Carmarthen West and South Pembrokeshire.
There is no evidence that a man killed during a north Belfast riot 46 years ago was holding an explosive device when he was shot, an inquest has heard.
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The Conservatives have won the constituency of Gower - a seat Labour has held for more than 100 years.