An elderly woman in Queens was critically injured when she was run over by a city bus — and may lose both her legs, authorities and sources said.

The 84-year-old woman was crossing Queens Boulevard near 108th Street in Forest Hills at around 10 a.m. when she was crushed by the right rear tires of a Q64 bus, according to cops and the MTA.

The bus was making a right hand turn onto Queens Boulevard when it struck the woman and rolled over her, causing her to lose at least one of her legs, sources said.

She was rushed to Bellevue Hospital in critical condition, fire officials said.