The three, ages 16, 15, and 14, are accused of abusing Louis Wright, and the child's 18-year-old mother, Shakera Wright, is accused of allowing the beating to occur, according to North Charleston police. She remained in jail Friday on a $40,000 bond.
Police were called to a hospital Tuesday after Louis arrived with face swelling, five fractured ribs, blood in his throat, bruises, and lacerations to his spleen, liver and pancreas. A brain scan revealed an old skull fracture that had healed, according to a police report.
Wright told a social worker the teens "play-wrestled" with him Monday evening. Making boxing motions with her fists, she said they hit her son until she stopped them because she thought the hitting got too hard, according to the report.
She said she didn't notice anything was wrong until the next morning, when Louis wasn't as "playful as usual," and she called 911.
According to arrest warrants, the oldest teen admitted abusing the child but called it wrestling. He was charged as an adult with inflicting great bodily injury on a child and held on $80,000 bond.
The police report said Wright and her twin sister were staying with the oldest teen. The Associated Press is not naming him because he is a juvenile. The other teens were charged as juveniles and have not been identified.
The arrest warrant for the oldest teen says he waived his right to a lawyer and admitted dropping the toddler on the ground and hitting him in his shoulder.
He said he and his friends "wrestled" with the child for about 30 minutes, including lifting him above their heads and slamming him on a bed, when his head might have hit a table.
Both charges -- inflicting the injury and allowing the injury -- are felonies punishable by up to 20 years in prison.
The Department of Social Services took custody of Louis.
It was unclear whether Wright had a lawyer.