Figure 17: shows the correct angulation of the shoulders and upper arm (set at 90 degrees). The correct form can be gauged by the width between the point of the breastbone and the back of the shoulder (as shown by the dotted lines).
Figure 18: shows the shoulder blade too steep and the upper arm joined at an angle greater than 90 degrees. Note also the less prominent forechest ("flat front") which often accompanies upright shoulders; and the forelegs that are placed too far forward. The dotted lines also highlight the lack of width between the point of the breasbone and the top of the shoulder.
Figure 19: shows futher exaggeration, leading to knuckling over of the forelegs.
Figure 20: seen from the front, upright shoulders may, in bad cases, also cause the elbows to stand out from the ribs. The body should not hang loosely betwen the legs.