Gaten Matarazzo says doctor warned arm trick he's been doing for years could have caused his spine condition

Stranger Things star Gaten Matarazzo says doctors have warned that his famous arm trick could have caused his spine condition.

On-screen, he's best known to the world as his character Dustin - a faithful friend and bestie/brother figure to Steve Harrington.

Off-screen, the actor, with no collarbones, previously went viral for showcasing how he is able to bend his arm back behind his head.

However, when he was asked at a convention last year to do his trick, he politely declined.

In a clip from 2022, shared by TikToker Paige Della, a fan asked the actor to 'do the arm thing' to which he explained why doctors told him to avoid doing it.

Matarazzo, who has been diagnosed with cleidocranial dysplasia - a rare genetic condition that affects teeth and bones - also happens to suffer from scoliosis - an abnormal twisting and curvature of the spine.

TikTok/@paigedella

Explaining why he refused the fan request, Matarazzo said on-stage: "I'm good. I'm going to skip doing the arm thing because I was just at a conference for my - for CCD Smiles - it's a charity about cleidocranial dysplasia.

"And one of the physical therapists there was like 'stop doing that'.

"I was like 'oh!'.

"He's like 'it's not good for your shoulders and back'.

"I'm like 'well I've been doing it for 20 years'.

"And he's like 'well... that's probably why you have scoliosis'.

"Like okay cool.

"So I should refrain."

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Also addressing his cleidocranial dysplasia back in 2018, he told The Doctors that his condition was 'one of the biggest reasons' why he hadn't been getting roles.

But when he auditioned for Stranger Things, he started explaining what it was, and later learned it would be incorporated into the show.

"Once I got the part, they said they’re gonna incorporate that and use it in a realistic way," he said.

"They asked me if it was okay if the kids in the show had bullied me because of it. I said it’s totally cool. It’s realistic."

And again chatting on The Jonathan Ross Show in 2016, Matarazzo went into more depth, explaining: "It's a condition where you are born without your collarbones; I don't have any. It affects your facial growth, your skull growth, it affects your teeth.

"That's why I don't have any - these are fake - I have teeth but they're all baby teeth.

"I just want to raise awareness for it and let people know that it's not something that you should be afraid of showing."