Lawyers for David Dao, the passenger forcibly removed from a United Airlines flight over the weekend, confirmed that Dr Dao had sustained several serious injuries as a result of his removal. The injuries include a concussion, broken nose, injury to the sinuses, and two lost teeth.

Attorney Thomas Demetrio told reporters Dr Dao was discharged from the hospital late on Wednesday. He described his client as "shaken”, and suffering from some memory loss.

Dr Dao was forcibly removed from United Airlines flight 3411 on Monday, after refusing to relinquish his seat to United Airlines crew members. Dr Dao, who had purchased a ticket and taken his seat, was dragged from the aircraft by several police officers. Video posted by fellow passengers show Dr Dao crying out in protest, and later appearing in the cabin with blood on his face.

The video drew outcry on social media, and sparked calls to boycott the airline.

Dr Demetrio said at a press conference on Thursday that there would “probably” be a lawsuit over the incident. Dr Demetrio and co-counsel Stephen L Golan filed an emergency petition with a Chicago court on Wednesday, asking United Airlines and the city of Chicago to preserve all evidence that could pertain to a suit.

The firm’s current role, Dr Demetrio said, is “just to get the facts, and get them out”. He claimed to have been contacted by hundreds of United passengers, employees, and former employees alleging mistreatment by the airline. He framed Dr Dao's case as a rallying point all dissatisfied passengers and employees.

“For a long time airlines – United in particular – have bullied us,” he said. “They have treated us less than maybe we deserve … Forget the law for a minute, that requires common decency in the treatment of passengers, but just treat us with respect.”

On the subject of the law, Dr Demetrio claimed police officers had breached it when they used force to remove Dr Dao from the plane.

“Here’s the law, real simple: if you’re going to eject a passenger, under no circumstances can it be done with unreasonable force of violence,” Dr Demetrio said, daring anyone who had seen the video to claim excessive force had not been used.

Three officers from the Chicago Department of Aviation have been put on leave pending an investigation of the incident, a department spokesperson told The New York Times.

Dr Demetrio also criticised United’s response to the incident, calling the airline’s apology “staged”. United CEO Oscar Munoz initially refused to take responsibility for the incident, but later reversed course after his tepid response generated backlash.

"I think my reaction to most issues is to get the facts and circumstances," Mr Munoz said in an interview with ABC News on Wednesday. "My initial words fell short of truly expressing the shame."

Dr Demetrio said his firm would not be pursuing a class action lawsuit against the company, but did not rule out the possibility of a civil suit. He also shot down accusations that United had racially profiled his client, who is of Asian descent.

“I don’t think this is a matter of race at all,” Dr Demetrio said. “... I think what happened to Dr Dao could have happened to any one of us.”

Dr Dao’s daughter, Crystal Dao Pepper, appeared at the press conference alongside the attorneys. She thanked the hospital staff who had treated her father, as well as those who had contacted the family with their thoughts and prayers.