The one-and-a-half-year old child is being treated at the Ernakulam district general hospital here.
Her condition is stated to be stable, police said.
The girl suffered the injuries after being tortured by her mother and her lover during the child's month-long stay with the couple in Kozhikode, they said.
The woman had allegedly eloped with her lover a month ago and the child was staying with them, police said.
According to the police, the duo had admitted the child to a private hospital in Kozhikode. Later, the woman sent the child to her parents here.
District childline officials said they were informed about the incident yesterday by the hospital authorities following which the infant was shifted to the Ernakulam district general hospital and the police informed.
An investigation has been launched based on a complaint by the child's father, police added.