HBO’s ‘Marathon’ is a portrait of deep wounds and true grit

More important than the shock, horror, fear, and anger that the terrorist bombing of the 117th annual Boston Marathon on April 15, 2013, aroused here and around the world, Ricki Stern and Annie Sundberg’s documentary “Marathon: The Patriots Day Bombing” recalls the pride and solidarity of a city sorely wounded. And its determination to heal. This latter virtue is especially on display in this restrained, eloquent, and artfully composed documentary.

It recalls events ingrained in every Bostonian’s memory: the beautiful weather at the beginning of the day, the initial jubilant spirits, the incredulity and shock of the two blasts. And then the ghastly spectacle of blood and mangled debris covering the pavement, the panic, and the swift action of first responders and common people whose uncommon actions doubtlessly saved the lives of many of the injured. Three died in the bombings, but the toll might have been much higher without their bravery and resourcefulness. Though some of these heroes are briefly mentioned, the film might have spent more time profiling them.

Be that as it may, “Marathon” excels at compiling press photos, ubiquitous surveillance footage, news clips, and amateur videos and weaving them together into a narrative with the momentum of a well-crafted thriller. The events are intensified and personalized by showing them from the point of view of three groups of survivors. They are victims who, like the travelers in Thornton Wilder’s novel “The Bridge at San Luis Rey,” came from different places and backgrounds and happened to end up at the two spots where bombs exploded among the spectator-jammed sidewalks of Boylston Street. The chaos of those moments takes on an extra dimension of terror because we feel we know some of the people who were damaged so grievously.

They include Celeste Corcoran, who with her husband, Kevin, daughter Sydney, and son Tyler, were cheering at the finish line for Celeste’s sister, who was running in the race. Celeste lost both legs. Sydney sustained critical injuries, including a severed femoral artery. Her life was saved when a stranger, a veteran, inserted his hand into the wound and squeezed the artery shut. Globe photographer John Tlumacki took a picture of the moment and it was reprinted in newspapers around the world, becoming a signature image of the event. The HBO film was produced in association with the Boston Globe.

Kelly Norden with husband J.P., who was wounded in the bombings. J.P.’s brother, Paul, also lost a limb.Globe Staff/File

Brothers Paul and J.P. Norden each lost his right leg in the second explosion, which is caught in a horrific on-the-spot video. They were treated at separate hospitals, with Paul put into a medically induced coma for nine days and J.P. suffering burns over 50 percent of his body. Their mother, Liz, had to rush from one hospital to the other to be by their sides as they underwent repeated surgeries.

Newlyweds Jessica Kensky and Patrick Downes, themselves avid runners who had finished the Boston Marathon in 2005, were this time spectators at the finish line. Each lost a leg in the bombings, with Jessica’s remaining leg so damaged that she had to receive months of brutal physical therapy at Walter Reed National Military Medical Center in Bethesda, Md.

These are not feel-good stories. Sydney Corcoran fell into deep depression and developed an eating disorder. Her father resorted to drink. Kensky, after many months of pain and disappointment, had her remaining leg amputated. She experienced mixed feelings when her husband, equipped with a racing blade, prepared to enter the 2016 Boston Marathon. And Liz Norden says she watched the video of the explosion that took her sons’ limbs more than 3,000 times, trying to make sense of it all.

The film doesn’t attempt to do that. Though it touches on the anxiety the city felt during the manhunt for Dzhokhar and Tamerlan Tsarnaev, and on Dzhokhar’s trial and death sentence, it doesn’t dwell on the background or motives of the two brothers who planted the bombs. Instead it focuses, rightly so, on the survivors, still courageously trying to overcome their wounds — and on those who didn’t survive, to whom the film is dedicated.

★ ★ ★
Marathon: The Patriots Day Bombing 

Directed by Ricki Stern and Annie Sundberg. At the Coolidge Corner Theatre, beginning Friday. Partial proceeds from a special screening Sunday at 2 p.m., featuring a Q&A with the filmmakers, will go to the One Fund Center at MGH. It will also be broadcast on HBO, Nov. 21 at 8 p.m. Unrated. 105 minutes.

Patrick Downes, a bombing survivor, in the film “Marathon.” John Tlumacki/Globe Staff