bend the elbow

In common parlance though, when someone mentions the elbow they usually mean the pointy bit; the outside of the arm bend.

虽然从通常意义上讲，当一个人说到手肘的时候，他所指的常常是肘关节尖端的那一小部分，也就是手臂弯曲处的外侧。

Is there a name for the inside of the arm bend; the crease inside your elbow?

但是有没有一个词专门指手臂弯曲处内侧，也就是手肘内侧的褶皱处呢？

Bend your left elbow and twist your torso to the right, dropping the left shoulder and the whole left side of the torso as low as possible on your inner left thigh.

曲左肘，上身向右扭转，左肩和上身左侧尽量沿左大腿内侧向下落。