A large weave pattern injury across the back of Richard's scalp was consistent with his head hitting the carpeted area of a floor, she said.
Richard's mother, whose victim impact statement was read to the court, said she was "heartbroken", and still suffered nightmares, and had at one stage turned to drugs and alcohol to "try and numb her pain".
The loss of her son meant she would never get the chance to watch him walk, run, learn to talk, go to school, or see him grow into manhood.
"I will never hear Richard say 'I love you mum' and have a hug. This is every parent's dream, which has been taken away from me," the grieving mother said.
"I feel Richard has been wiped out of our lives ... and I fear the way he died he must have been in pain which no child of any age should experience.
The mother said she hoped the prisoner got help in prison to see the "error of his ways".
But no matter how long a sentence he received it would never be as "long or as painful" as the one she was serving because of the prisoner's actions, she said.
Richard's grandmother, whose victim impact statement was also read to the court, said she and Richard's father would also never get over her grandson's murder.
"I hope every time you hear a baby cry it will remind you of the pain you have inflicted on my defenceless 14-week old grandson.
"I hope you will use the time in jail to reflect on the emotional damage you have caused our whole family," she said.
Justice Mary Peters told the prisoner he must serve 14 years and six months of his sentence before he would be eligible to apply for parole.
Crown solicitor Anna Pollett argued that given the high degree of brutality and vulnerability of the victim a minimum non-parole period of 17 years was not manifestly unjust.
But she accepted discounts for the prisoner's youth and a modest discount for his particular personal circumstances was appropriate, she said.
Defence lawyer Rob Stevens argued a further three years' discount was warranted.
Mr Stevens said that would reflect the fact that his client would "indeed be serving hard time" after being assaulted in prison and the prisoner genuinely feared for his safety.
Justice Peters disagreed, saying the prisoner's safety was a matter for the Corrections Department and not something she could legally take into account.
The judge said she was satisfied the prisoner had not meant to kill the baby, but he would have known assaulting a defenceless 14-week-old baby was likely to cause his death.
"Richard Uddin was a lovely little baby, and his death is tragic for everyone ... No one but you knows precisely what happened but Richard's injuries tell a powerful story," she said.
Justice Peters said she was "startled" when she read the prisoner's pre-sentence report.
It was clear that he was yet to grasp the magnitude and gravity of his actions, she said.