Arthur is a good fielder but he's got a glass arm.

亚瑟是个好外野手，却有一只容易酸痛的手臂。

youdao

He balanced the glass precariously on the arm of his chair.

他把杯子放在椅子的扶手上，随时可能摔下。

《牛津词典》

I muttered, knocking my knuckles through the glass, and stretching an arm out to seize the branch; instead of which, my fingers closed on the fingers of a little, ice-cold hand!

我咕噜着，用拳头打穿了玻璃，伸出一个胳膊去抓那条树枝。可我的手指头没抓到它，却碰着了一只冰凉小手的手指！

youdao

Behind a tinted glass panel 18-carat gold powder, laid down by a robot arm, sparkles as a laser fuses the metal into complex three-dimensional shapes, layer by layer.

BBC: How tech is transforming jewellery

So I squeezed into the crumpled passenger area, sat on the shattered glass, and tried to take the pulse from his passenger-side arm (nothing) and his neck (nothing).

NPR: 'Operation Homecoming': The Writings of War