Throwing Arm Rotation

I thought I should add some more detail involving the throwing arm from the cocked position to the release of the ball. As the shoulders turn (after the ball is in the cocked position), the elbow leads the hand to the release point. The forearm rotates back. The maximum rotation back should be approximately 180 degrees. In other words, the point from the throwing elbow to the wrist should be horizontal right before the ball is brought forward to the release position. At this point the pitcher's back should be arched and the forward position of the elbow should be just in front of the throwing side hip. Checking a pitcher for good arm rotation prior to release must involve film which should be shot at a right angle from the pitcher's throwing side.