Henry Winkler, right, watched his mother, left, struggle with upper limb spasticity.

It’s no surprise that a Hollywood celebrity is promoting Botox. But the reason Henry Winkler is giving the neurotoxin two thumbs up in Washington today probably isn’t one you’d expect: He’s working as an ambassador to promote the use of Botox in treating upper limb spasticity (ULS).

You might not know the condition by name, but you’ve seen it before, promises the actor, best known as “the Fonz” from “Happy Days.”

“The arm, hand, wrist or fingers freeze up in odd shapes. The fingers push into the palm, the upper arm is frozen into the chest or out like a wing,” says Winkler, who watched his mom suffer with ULS for 10 years after a stroke in 1986. Not only was it physically debilitating, it was also embarrassing.

She was an active woman who ran a shop at her synagogue and regularly played bridge and canasta with friends. “And it all stopped,” Winkler says. “I watched the will to live drip out of this woman. She didn’t want to go on a walk anymore, didn’t want to get in a wheelchair for a push.”

Botox wasn’t an option for his mom, but patients these days can get an injection to release frozen muscles. “You don’t get use of the hand back, but you get the ability to try therapies on it,” he says.

The treatment also boosts self-esteem by giving patients the opportunity to wash their hands, clip their fingernails or dress themselves.

As for Winkler’s self-esteem, he’ll be testing it on this D.C. trip when he visits his old leather jacket at the Smithsonian. He’ll look, but he won’t be putting it on.

“The fear is it will not fit exactly the same way,” he says. “And I don’t want to be the one to find that out.”

Meet Up

Patients and their caregivers are invited to hear Henry Winkler, along with neurologist Laxman Bahroo from Georgetown University Hospital and other speakers, at 2 p.m. today in the Federal A/B Room of the Capital Hilton (1001 16th St. NW). For more information about upper limb spasticity, visit Openarmscampaign.com.