A female patient with a serious brain injury was raped at Bronx-Lebanon Hospital, police sources said Sunday.

A registered nurse at the hospital was checking on the 32-year-old patient around 7:45 p.m. Friday when she walked in on Keith Nembhard, 37, having sex with the incapacitated woman, police said.

The victim’s doctor told cops that the woman had a brain injury that rendered her incapable of consenting to sex, according to sources.

Nembhard, who knew the victim, was apprehended, arrested and charged with rape in the second degree, sources said.

Additional reporting by Stephanie Pagones