Noun:

1. the part of the aorta that arches and turns downward

A Bao阿宝aart.一(个)；每一(个)；任一(个)n.英语字母表的第一个字母；学业成绩得优者；表示“最好”的符号a shy gawky teenager一个腼腆而笨拙的十几岁的孩子a vessel of mercy.慈悲的化身A rmoracia rusticana辣根a teacher of English英语教员a tribe of cannibals食人部落a dream of greatness梦想伟大a sour face/smile阴郁的脸色；苦笑a surplus population过剩的人口a tug of war contest拔河比赛a sparkling red star闪闪的红星

1. The main pulmonary arteries are derived from the sixth aortic arch during intrauterine development.
   摘要肺主动脉是在胎儿时期时由第六对主动脉弓衍生而来。
2. The association between arch plaques and hypercoagulability, and its effect on the stroke risk, was assessed with a case-control design.
   利用病例对照研究分析主动脉弓斑块与高凝状态的关系及其对卒中危险的影响。