Bird sternums have a projection from the middle called the keel, and this is where the flight muscles are attached.

鸟的胸骨中间有一个隆起的部分，叫做龙骨突，这是飞行肌肉附着的地方。

Next, we inserted the ground wire into the flight muscle of the wing.

接下来，我们将地线插入机翼的飞行肌肉中。

And the keel-like protrusion on their sternums, where the flight muscles attach, shrinks or disappears, except in penguins, who repurpose their flight muscles and keels for swimming.

它们胸骨上的龙骨状突起（飞行肌肉附着的地方）会收缩或消失，但企鹅除外，它们将飞行肌肉和龙骨重新用于游泳。