Authorities say there were also signs of sexual assault.
Johnston County Sheriff Steve Bizzell says it is one of the worst cases of child torture that he's ever witnessed.
Deputies arrested 21-year-old Jonathan Douglas Richardson after he took the girl to Johnston Memorial Hospital.
Authorities say he told them that the girl fell out of bed.
Bizzell tells ABC11 Eyewitness News that the girl was living with Richardson and her mother in an outbuilding/barn on Richardson's grandparent's property just east of Smithfield in Brogden Community.
The girl's mother, Richardson's girlfriend, was deployed to New Mexico for Army Reserve training on July 6.
Richardson has been charged with one count of felony child abuse severe bodily injury and is currently in jail under a $1 million bond.