The lower traps run from the your spine up and out in a V-shaped pattern towards the lower, inside edge of your shoulder blades. They pull your shoulder blades down and inward.
When your arms are at your sides they are much shorter than depicted here. In that position, you can use a tennis ball in a sock or a well designed tool like the BackKnobber to reach trigger points in your lower traps.
This reclining position allows you to completely relax the shoulder while compressing these trigger points.
Serratus anterior comes off your ribs and attaches your shoulder blade. It pulls your shoulder blade down and out. To reach your serratus anterior, we recommend using two tennis balls in a