They have this streamlined sternum with lower sternal keels.

它们拥有流线型胸骨，龙骨突较低。

Birds with a deep sternal keel fly more slowly, those with long sternums are associated with running birds.

龙骨突深鸟飞得更缓慢，而胸骨长鸟则大多是走禽。

Also, that blood flowing through a VSD can be heard as a holosystolic murmur at the lower left sternal border.

并且，血液流经VSD时，在左下胸骨诊就会到全收缩期杂音。

Then, if you place a stethoscope in the left second intercostal space, at the left upper sternal border, you can hear the pulmonary valve closing.

然后，你将诊器放到左第二肋间隙，在左胸骨上，你将到肺动脉瓣关闭声音。