ALYSSA NEWCOMB & ANTHONY CASTELLANO, ABC NEWS - The boy who died after waiting for his dad to finish the Boston Marathon Monday when two bombs exploded seconds apart was a typical 8-year-old who loved to ride his bike and play baseball, according to a neighbor.
Martin Richard died from the explosion that injured his mother and sister as they all waited for his father to finish the race, according to ABC News' Boston affiliate WCVB-TV.
A single candle was placed in front of his home overnight in Dorchester, Mass.
"There are no words to describe how they are feeling ... we are feeling," neighbor Jane Sherman told WCVB, adding that the family is close-knit.
The death toll from the twin bombings stands at three. Police announced Tuesday morning that 176 people were injured in the attack, with at least 17 still in critical condition.
Dr. Vivek Shah was among those who provided on-site assistance He had just crossed the 26.2-mile finish line at the marathon Monday when he was forced to put his medical skills to work.
"I've never obviously been in combat, but people I've trained with have been and this is as close as I can imagine it would be," Shah told ABC News Radio late Monday night. "Just, basically piles of victims. Everything I saw was a traumatic amputation, basically."
Shah, an orthopedic surgeon at New England Baptist Hospital in Roxbury Crossing, Mass., said he saw injuries along the sidewalks on Boylston Street for which no amount of training could prepare him.
"In all my medical training, I have not seen things that I saw [Monday]. Everything was traumatic," Shah said.
Spectator Aaron Hern, 11, of Martinez, Calif., was another young victim injured when flying shrapnel dug into his thigh as he was waiting for his mother to cross the finish line. Hern is being treated at Boston Children's Hospital.
"He was waiting for his mom to go through the finish line to take pictures of her and shortly before she got there, the bomb went off," family friend Janene Sides told ABC News affiliate KGO-TV.
On Facebook, Aaron's mother, Katherine, said her son was in stable condition in the ICU late Monday night. Hern said Aaron would have additional surgeries and is expected to be hospitalized for seven to 10 days.
Hern's injuries are similar to what doctors at two Massachusetts hospitals described Monday night, hours after the explosions. Some of the most critical patients sustained lower extremity injuries from debris.
Dr. Ron Walls, chair of emergency medicine at Brigham and Women's Hospital, said doctors did not identify any shrapnel, such as ball bearings, but saw a lot of "street stuff" that had injured their patients.
"Rocks, bits of metal, soda cans, anything that is really close to a blast like that can be fragmented," he said. "Everything we saw was ordinary material that could have been propelled by the device."
Of the 31 patients who were transported to Brigham and Women's Hospital after the blast, nine are in critical condition and one person has "life-threatening" injuries, Walls said.
It was a similar scene at Massachusetts General Hospital, where trauma surgeon Dr. Peter Fagenholz said he found "a lot of small metal debris" in victims.
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Of the 29 patients he said were seen at the hospital, eight were in critical condition.
"The most common serious injuries are combined lower extremity injuries," he said, which included bone and soft vascular trauma.
Fagenholz said several amputations had been performed at the hospital today and he had seen at least one ruptured ear drum.
"A number of patients will require repeat operations tomorrow and serial operations over the next couple of days," Fagenholz said.
Children Among the Victims of Blasts
On a public school holiday in Boston, Patriots' Day, children were also hit hard by the explosions.
Some of the youngest victims were taken to Boston Children's Hospital, where officials said their conditions ranged from good to serious.
Other injured included a 7-year-old boy who was being seen in the emergency room for a minor leg injury and a 12-year-old with a femur fracture, hospital officials said.
The 42-year-old parent of a patient was also being treated in the emergency department and three additional patients were in good condition, according to the hospital's evening update.
At Tufts Medical Center, nine people were being treated for "significant but not life-threatening injuries," WCVB reported.
Four of the surgical cases were serious orthopedic and neuromuscular trauma to the lower legs, with open fractures, while other patients suffered shrapnel wounds and ruptured eardrums, hospital officials said.