The death of a 4-month-old Bronx boy who police had been told fell off a couch has been ruled a homicide, officials said Tuesday.

Tiny Christopher Rhodes died Aug. 7 at Jacobi Medical Center after suffering head trauma and injuries to his torso.

The infant’s father told police he had been feeding Christopher on the couch when he stepped away for a second and the child fell to the floor, striking his head.

But months later, it was discovered the baby’s actual injuries were more severe than initially believed, police said.

An autopsy revealed that the infant suffered a fractured skull, a collapsed lung and internal bleeding, police source said.

No arrests have been made, and police continue to investigate.