Tadhg Costello (18) of Richmond Hill, Monkstown has pleaded not guilty to the attempted murder of Josh Leahy (18) at Johnson's Court in Dublin city on May 31, 2012.
He also pleaded not guilty at The Central Criminal Court to assault causing harm to Mr Leahy and unlawful possession of a knife on the same date.
The evidence of a consultant cardio-thoracic surgeon was read to the court by Mr Paul Burns SC prosecuting.
Mr Michael Tolan said Mr Leahy was reviewed at St James’s Hospital on May 31 2013.
Mr Tolan said Mr Leahy was stabbed six times in the back with wounds in the upper and lower part and one in the midline.
The surgeon said a chest drain was inserted and there was good re-expansion of the lung.
Mr Tolan said the chest drain was removed on June 1, 2012 and Mr Leahy was discharged on June 2.
Garda Michael O’Shea said he was on plain-clothes mobile patrol with Garda Mark Eccles on Grafton Street on May 31, 2012.
Gda O’Shea said a description of a group of males involved in a fight came over the radio.
He said when he arrived at St Stephen’s Green some of the men had got into a taxi and a few of them were standing waiting to get into it.
Gda O’Shea said they identified themselves as gardai and asked the men to get out of the taxi.
He said he observed the accused throw a shiny object behind the rails and Gda Eccles then got over them and recovered a knife.
Under cross-examination by Mr Damien Colgan SC defending he disagreed that Gda Eccles took a note of what the accused was saying before the knife was retrived.
“When the knife was thrown there was an immediate search of the railings,” said Gda O’ Shea.
But Mr Colgan said that he had indicated in his statement that the knife went through the railings.
Garda Damien Beakey said he was driving his patrol car up Grafton Street shortly after 3am on May 31.
He observed three males walking slowly and could see blood on one of their backs.
Gda Beakey said they all spoke to the gardai and informed them a fight had taken place.
He said one of the males was struggling to talk, was out of breath and he was taken to hospital by ambulance.
Gda Beakey said he got a description of the males who were suspects in the assault and he asked the injured party’s two friends to go around in the back of the patrol car with him.
He said Gda Eccles called 10 or 15 minutes later and went up to St Stephen’s Green North.
Gda Beakey said he observed eight males standing there and one of the injured party’s friends, Emmanuel Mihaylov, positively identified the group.
He said Mr Mihaylov pointed out the defendant as being the person who had the knife earlier in the night.
Gda Beakey said he saw the defendant throwing something behind him through black railings and that Gda Eccles got over the railing and picked up a knife.
Under cross-examination Mr Colgan put it to him that Mr Mihaylov said in evidence that he had not seen the stabbing.
But Gda Beakey said that he thought Mr Mihaylov told him the accused was the person involved in the stabbing and denied changing his evidence from his statement.
The trial, which is now in legal argument, continues on Monday with Mr Justice Paul Butler presiding.