The independent appeal committee, chaired by Professor Lorne Crerar (Scotland) and also comprising Rod McKenzie (Scotland) and HHJ Jeff Blackett (England), found that Quinlan had not demonstrated that the original decision had been in error, or that it should be overturned or varied.
Accordingly, the appeal committee dismissed the appeal and upheld the suspension imposed on the player of 12 weeks.
He wss found to have made contact with the eye area of Leinster captain Leo Cullen during the Heineken Cup semi-final match between Munster and Leinster at Croke Park on May 2.
The 12-week suspension is for twelve playing weeks. The off-season is not included in the period of ineligibility and Quinlan will be eligible to resume playing on September 10.