A former Navy sailor who, according to a doctor, inflicted the "worst case of serious physical injury she has seen in her career" to a child, pleaded guilty Wednesday to abusing his then 2-month-old son.

Jordan Rittenhouse, 25, who was stationed in Groton, pleaded guilty to two counts of risk of injury to a minor. He will be sentenced on July 9 to 20 years in prison, suspended after eight years served followed by five years' probation.

Groton Town police began investigating on Aug. 26, 2014, after receiving a report of possible child abuse from the state Department of Children and Families, according to an arrest warrant affidavit. The child's mother had taken the child to Lawrence + Memorial Hospital in New London because he was not eating properly. He was transferred to Yale-New Haven Hospital after doctors found multiple rib fractures.

At Yale, Dr. Andrea Asnes, head of the hospital's detection assessment referral team, reported the child had 29 bone fractures showing various degrees of healing. She said some were consistent with squeezing injuries, but the baby also had fractures of the extremities not consistent with squeezing. She described it as one of the worst cases of serious physical injury in her career and said she was surprised the baby was alive.

During an interview with police, Rittenhouse, who was attending the Naval Submarine School and living in Navy housing at 53 Deerwood Drive, said he had been under a lot of stress. He admitted he had squeezed the baby several times, sometimes so hard that the child stopped crying, and had once shoved the baby’s bottle into his mouth, causing the infant’s mouth to bleed.

"Rittenhouse recalled one occasion when he squeezed the victim that he was concerned that he may have punctured a lung," the warrant says.

Originally from Rockwell, N.C., Rittenhouse enlisted in the Navy in November 2013, according to a Navy spokesman. 

i.larraneta@theday.com

Twitter: @larraneta