But if you use a cordeo (correctly) it causes the horse no pain.
Look at the diagram above. If the cordeo is placed too far up on the horse, it could hurt the thyroid gland, trachea, esophagus, and external jugular. The cordeo should lie just in the crest of the neck, above the horse's shoulders and lie loosely over the withers.
If it is kept that way, it'll be against the brachiocephalicus muscle, and won't injure the horse.
Avoid the common mistake of pulling too much on the cordeo, or letting it slip too far up the horse's neck toward the head. It should remain around the shoulders.
It should look like this:
When most people say that they are searching for answers and truth, what they really want is to hear what suits them. How often is the answer really coming from the horse? -Michael Bevilacqua