Richmond County Sheriff's Office arrested Darnasia Hadden, 18, of the 1900 block of Murphy Road, said sheriff's Lt. Calvin Chew.
Deputies were dispatched to the family's apartment about 3 p.m. Tuesday after a 911 hang up. Deputies reported that upon arrival, they found the boy with bruises, swelling and cuts on his head.
"He was beaten to the point of throwing up," Lt. Chew said. "Apparently, he had broken her cell phone, and she got upset."
The victim was sent to the Medical College of Georgia Hospital and Clinics for examination, and was later released. The child will remain in the care of his mother, who phoned the police about the beating.
Hadden remained Tuesday morning at the Richmond County Jail.