pectoralis

(anatomy) A pair of muscles that lowers the wings of birds in flight

Japanese Meaning

鳥の飛行時に翼を下げるための一対の筋肉

The migratory goose relied on its pectoralis to power the strong downstroke during long flights.

その渡りガチョウは長距離飛行中に力強い下打ちを生み出すために胸筋を使った。

Sense（1）

(anatomy) A pair of muscles that lowers the wings of birds in flight