When asked to describe playing on both sides of the Rangers-Islanders rivalry, hockey Hall of Famer Pat LaFontaine remembers two nights.

In the first, while with the Islanders, he was being transported from Madison Square Garden to the hospital after suffering an injury.

“The ambulance was shaking and I could hear Rangers fans yelling, ‘I hope you broke your neck,’ ” he recalled with a chuckle Tuesday night, at the New York premiere of the documentary “The NHL: 100 Years.”

About a decade later, with the Rangers, he scored a big goal against his former team at the Garden. “I swear I heard someone scream, ‘I’m glad you’re alive, LaFontaine!’ ”

The St. Louis native added that he and the other stars at the Paley Center premiere — Rangers legend Rod Gilbert, Islander Hall of Famer Bryan Trottier and former New Jersey Devil Ken Daneyko — are now all part of the “NHL fraternity,” and it is that mix of competitiveness and camaraderie that makes the NHL, which was established on Nov. 26, 1917, and “The NHL: 100 Years” compelling.

The two-hour documentary covers the league’s beginnings, the Original Six era (which includes the Rangers), 1960s expansion and the league today. Legendary players, including former Rangers Wayne Gretzky and Jaromir Jagr, share their memories of the game, as do a number of writers and historians.

“This is a sport of great history and tradition,” said NHL commissioner Gary Bettman, who is in his 25th year heading the league. “This film is an attempt to take that history and, in two hours, give viewers a chance to see how awesome it is.”

The documentary debuted last weekend on the NHL Network and on NBCSN, and will be rebroadcast on NHLN this Saturday at 1 p.m. and again Sunday at 4 p.m. Fans can also stream it on NHL.com.