I Can't Believe I Just Noticed The Best Detail About Bucky Barnes' Arm In The MCU

Published Apr 6, 2025

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Out of all the impressive superhero costumes that the in-universe technology has advanced so much since Phase 1, which has allowed for more elaborate suits than before, even for the MCU’s humans. Characters usually wear an updated iteration of their costume in each new project. Sometimes the changes are minimal, but other times a drastic switch can represent something going on in their story.

While Bucky is one character whose clothes have stayed relatively similar over the years, his prosthetic arm tells of his MCU evolution. He originally received his prosthetic under tragic circumstances. After falling from the train in Captain America: The First Avenger, HYDRA found him missing his left arm. They gave him a titanium prosthetic that was impressive in strength and durability but led to his stint as the Winter Soldier. Bucky later got a new vibranium arm from the Wakandans, and the new prosthetic was the shift he needed into his era of atonement.

This Detail About Bucky's Arm In The MCU Is So Cool

Close up image of Winter Soldier's prosthetic arm blocking Captain America's shield in Captain America The Winter Soldier (2014)

Bucky’s prosthetic arm is part of what’s made him such an iconic character. Sebastian Stan’s reintroduction as the Winter Soldier in Captain America: The Winter Soldier is one of the MCU’s most memorable entrances. While fighting Steve, he’s even able to block hits from the Captain America shield. Fans have always been fascinated with Bucky’s arm because of its sleek design and incredible capabilities, but one detail about it has been flying under the radar.

Whether it’s Bucky’s original titanium arm or his upgraded vibranium one, the structure of the prosthetic has stayed relatively the same. It looks to be made up of individual plates so that it has more flexibility in battle than if it was just connected by an elbow t. It’s an incredibly cool detail that fans might overlook, and understandably so considering how quickly some fight sequences can move. Especially with that considered, it’s nice of Marvel to go through the effort of having each metal plate move when it’s easily a detail they could’ve omitted.

Bucky's Arm In The MCU Is Actually Great Whether It's Practical Or CGI

The moving metal plates in Bucky’s prosthetic arm are such a subtle detail, but it’s executed very well, whether it’s practical or CGI. In a recent interview to promote Thunderbolts*, Stan talked about how he’s always used a practical arm for the Winter Soldier. He prefers to avoid using CGI as it’s an easy way to point out inconsistencies, and practical costumes and props always allow for actors to be more immersed on set too. However, the metal plates on the prosthetic may be the one part that needs some help from visual effects.

It’d be incredibly impressive of Marvel to go completely practical on Bucky’s elaborate arm, but the logistics of it don’t seem realistic. The studio likely uses the practical arm as a base and then uses CGI for the plate movements on top. Even though the MCU has had some shaky CGI moments, Bucky’s prosthetic is a great example of how talented Marvel’s visual effects team is considering how seamlessly the metal plates move. With Bucky set to appear without his Winter Soldier costume in Thunderbolts*, the mechanics of his arm will hopefully be on full display.