Doctors attending to long-distance runners usually see overheating and dehydration, but on Monday after the bombings on the Boston Marathon finish line the injuries were so gruesome that some had no choice but to amputate once healthy legs.
Surgeons at Boston's biggest hospitals raced against the clock to save the lives of spectators and athletes who came in with legs so mangled that bones were sticking out and some limbs were hanging only by shreds of muscle.
"If these victims had spent even a few more minutes at the scene they would not be alive today," Alasdair Conn, chief of emergency services at Massachusetts General Hospital, said on Tuesday.
A team of 20 Massachusetts General surgeons, including one who had himself just completed the 26.2 mile (42.2 km) race, amputated four legs above the knee. At Boston Medical Center, surgeons performed five amputations and at Brigham & Women's there was one.
Two bombs exploded more than four hours into the race as hundreds of weary runners approached the finish line watched by thousands of spectators at one of the city's signature sporting events. So far three people, including an eight year old boy and 29-year-old woman, have died and 176 are injured, some critically.
What kept the casualties relatively low, doctors said in interviews and briefings, was that so many doctors, nurses, emergency medical technicians and ambulances were stationed at the finish to assist with the usually more routine ailments of the grueling event.
Doctors were able to quickly tell nearby hospitals what types of injuries were coming their way, they said.
Even seasoned veterans, including some who had worked in war zones, were shocked by the injuries, several doctors said.
"In my 20 years here I have never seen such a degree of casualties with such horrific injuries," said Michael Zinner, chief surgeon at Brigham and Women's Hospital, who supervised seven trauma teams staffed with orthopedic and general surgeons, anesthesiologist and nurses who operated long into the night.
"We saw lots of fractures and open wounds of the lower extremities, we had to check the blood flow and clean the wounds and that takes time. But so far, all survived," Zinner said.
Speed was critical and doctors across the city said it took them only minutes to wheel gurneys from emergency rooms to operating theaters to scrape out dirt and debris, set bones and sew patients up.
Doctors soon made grisly discoveries, finding 2- to 3-milimeter large metal pellets and tiny sharp objects that resembled carpenter nails lodged in their patients.
"Anyone who put together a bomb with ball bearings is going for maximum impact and in these cases it was the force of the blast that did the damage," said Ron Walls, Brigham and Women's chief of emergency medicine.
After doctors pulled out the debris, including metal shards from exploded trash cans, they handed them to federal investigators as evidence.
Many of the most critically injured were also burned by the blasts, and some are not yet breathing on their own, making it impossible to speak.
But others who woke up to the shock of finding that one leg is gone expressed gratitude.
"They thought they would die when they saw all that blood spilling out them and as they woke up today and saw that they were not dead, they told me they are extremely thankful," said George Velmahos, chief of Trauma, Emergency Surgery at Massachusetts General Hospital.