At least a dozen survivors have endured amputations.
Patients at Boston Medical Center have received visits from war veterans who have also suffered amputations. The vets, Dr. Jeffrey Kalish said, told patients that their lives aren't over because they've lost limbs.
"We've seen really tremendous success and great attitudes," he said.
Also Monday, Davis -- the Boston police commissioner -- said transit system police officer Richard Donohue, wounded in the firefight with the Tsarnaev brothers, was improving.
"He was in grave condition when he went to the hospital, so we're very optimistic at this point in time, and our prayers are with him and his family," he said.
Dzhokhar Tsarnaev, meanwhile, remains in serious but stable condition, according to the U.S. Attorney's Office District of Massachusetts. A federal law enforcement source with knowledge of the investigation told CNN the younger brother has a gunshot wound to his neck, and he had a tube down his throat to help him breathe.
It's unclear whether Tsarnaev was wounded during his capture or in the earlier shootout with police that left his older brother dead, said the source, who spoke on condition of anonymity.
Getting back to normal
It could take up to two more days before the area around the site of the explosions can reopen to the public, Davis said.
The FBI has not yet turned the scene back over to local authorities, the police chief said.
"We have to allow store owners to go in there first. It won't be open to the general public for maybe another day so the store owners can get their business back on track," Davis said. "We want to get people back in their homes as soon as possible, and we're working diligently on that right now."