The shoulder isn't easily visible as a shoulder to the general viewer, though. Granted, when they hear that there's a shoulder there (or look closely at that spot knowing that a shoulder is normally in that area), they'll realize it and see it clear as day. But it needs to be obvious from the moment the viewer's eye first sees the tag.
And the little bit of background you have isn't enough to create depth unless the viewer is looking directly at that area. Depth is a canvas-wide element to a tag, and needs to be represented across the entire canvas.