The MPSCA Angell Animal Medical Center said John Miles was walking his son's 8-year-old beagle mix, Lucy, near their home Nov. 25 when they were struck by a speeding car, the Boston Globe reported Wednesday.
The medical center cited reports from Boston Police saying the beagle limped to a nearby dentist's office, barked for help and returned to the side of Miles, who suffered two broken legs, a broken arm and 15 facial fractures.
Police used the address and phone number from Lucy's tags to contact the family of Miles, who was unconscious when they arrived.
Miles is recovering from his injuries in a rehabilitation center.
Veterinarians said Lucy will receive surgery to repair her leg.
"Lucy reminds us all of the important role animals play in our lives," veterinarian Meghan Sullivan said. "She's a true hero to John and her family and to all of us. We won't rest until she's back to her active self, enjoying long walks with her family once again."