απ'ότι λένε , οι βόμβες ήταν ειδικά σχεδιασμένες για να προκαλέσουν σοβαρά τραύματα στα κάτω άκρα και τοποθετημένες σε χαμηλό ύψος γι'αυτό το σκοπό :
Designed to propel shrapnel
Images in the immediate aftermath showed people being carried away on stretchers -- one man in a wheelchair had blood all over his face and legs.
While many patients were treated for cuts and scrapes, doctors have also been "pulling ball bearings out of people in the emergency room," suggesting the bombs were designed to propel shrapnel, according to one terrorism expert briefed on the Boston blasts, though CNN is yet to confirm this.
Medical teams have also carried out at least 10 amputations and treated many leg injuries, suggesting the device was low to the ground, according to CNN's Deborah Feyerick.
Among the 28 people taken to the city's Brigham and Women's Hospital, the most common types of injuries are to the bone and tissue, hospital spokesman Tom Langford told CNN.
He said nine of those patients have potentially limb-threatening wounds. A 3-year-old victim was transferred to Boston Children's Hospital for treatment.
Amputated limbs
Dr. Peter Fagenholz, a trauma surgeon at Massachusetts General Hospital, told reporters he treated many of the 29 patients who arrived at the hospital for shrapnel wounds.
"Many of the victims were hit with "a lot of small, metal debris," he said.
"Some people have asked already whether they were BBs or parts of bombs," he said, referring to earlier reports that ball bearings have been pulled from victims. "We can't say whether they were placed their intentionally or whether they were just part of the environment."
He said the most serious wounds "have been combined, complex lower injuries that involve blood vessels, bone and tissue." Some of the patients had to have limbs amputated, Fagenholz added.
"A number of patients will require repeat operations and serial operations over the next couple of days," he said, adding that he had been in surgery for almost 14 hours.
