This is the process of taking a porcelain to metal bridge from one side of the mouth to the other to stabilize the teeth on both sides. The strength of the metal prevents the teeth from moving out in lateral protrusion when the patient clenches his teeth. You are using one side of the mouth to stabilize the other side.
When you are considering constructing a horseshoe bridge, you need to think of it as a whole. It has retaining walls that must be converging with the other walls in the bridge preparations. By thinking of it as a whole it will be easier to bring all the walls into one unit of converging walls
For example: When the horseshoe bridge turns the corner at the cuspids, the distal walls of the bicuspids now must converge with the labial walls of the anterior teeth. By thinking of the bridge as a whole, it will make it easier to place the correct retentive walls and allow the bridge to seat.
One wall that is....