A doctor at Boston Children's Hospital said they removed BB pellets and nails from children. Dr. David Mooney says there were nails sticking out of one little girl's body.
Two children remain in critical condition at the hospital with serious leg injuries. Mooney said that tourniquets applied by emergency responders at the race saved the children's lives.
More than 170 people were hurt by the blasts. Doctors at Massachusetts General Hospital also say they removed metal fragments from victims of the bombs.
Hospitals began releasing more information Tuesday about the victims' injuries, including broken bones, amputated limbs and head injuries.