A 7-year-old girl accidentally ran over her toddler sister Tuesday while starting the family car at an apartment in Salem, N.H., police said.

The 2-year-old toddler was flown to Boston Children’s Hospital with injuries to her leg, chin, and scalp, as well as bruising on her rib cage and upper right arm, Salem, N.H., police said in a statement.

The girl’s mother told police she gave her daughter permission to start the car about 6:30 p.m., police said. While doing so, the girl put the Ford Focus in reverse and ran over her sister’s legs at the apartment on South Policy Street. The toddler had gone outside with the girl, police said. The 7-year-old yelled for help and the mother came out to attend to the toddler, the mother told police.

McGuinness can be reached at dylan.mcguinness@globe.com.