“指关节”的英语表达是 knuckle 。它既可以指单个的指关节，也可泛指手部的关节部位。例如：
He knocked loudly on the door with his knuckles.（他用指关节重重地敲门。）
You can see the bumps of his knuckles through his thin gloves.（透过他薄薄的手套，能看到他指关节的隆起。）