Then there’s flexion, where the fetal chin presses against its chest as its head meets resistance from the pelvic floor.

俯屈，胎儿的颏贴近胸壁，因为他的头遇到盆底肌的阻力。

Then, we also have an electrical motor over here that controls this transmission that you can see that controls flexion and extension of the elbow.

之后，我们里还有一个电机，它控制个传输，你可以看到它控制肘部的弯曲和伸展。

The isometric was an elbow flexion, aka a bicep curl, at maximal contraction held for 3 seconds 10 times at a 20-degree flexion.

精力训练做肘部屈曲，也就二头肌弯曲，以极保持3秒，以20度屈曲10次。

Cephalic, or head-first, is the first type, and furthermore the most common and optimal presentation for easy delivery is a type of cephalic presentation called vertex, which includes complete flexion of the head as well.

头先露，第一种类型；进一步说，对于顺产来说最常见的、最佳的先露，一种称为顶先露的头先露，包括完整的头部俯屈。