A prisoner inside a Bronx hospital pushed a cop to the ground and briefly escaped custody after she uncuffed him so he could use the bathroom, police sources said.

The suspect, Robin Valdez, 37, of the Bronx, made it out of Lincoln Hospital before police caught up to him on East 145th Street near Brook Avenue in Mott Haven at about 7 p.m. Sunday, authorities said.

It was not immediately clear why Valdez was initially in custody.

He was hit with several charges, including resisting arrest and assault, police said.

The officer suffered some bruising to the back of her head, cops said.