Credit: Sandy Rabinowitz TheseThese illustrations show a cross section of the horse's torso between his shoulder blades. The left illustration depicts the torso and withers dropped. The right illustration shows the torso and withers lifted. Note the different in the top line.
Credit: Sandy Rabinowitz Imagine a horse as he stands in his stall and looks expectantly into his feed bucket. He shapes his neck in an arch and there’s an element of reach in his stance. That’s the look of a horse that is “stepping through the poll.” When the horse is truly “stepping through the poll,” he allows the aids to travel through the neck and jaw.
Credit: Sandy Rabinowitz A horse with a correctly developed topline will have muscles in front of the withers that are as wide or wider than the muscles closer toward the poll, and the muscle under the neck is soft and loose. Oftentimes when the development of the horse is wrong, the muscles in the front of the withers are narrow and they become wider halfway up. If the width at the base of the neck is not there, it’s difficult or impossible for a bridge to exist.