When I think of topology the first I do is remember that size means nothing in topology.

So the long sleeve of the shirt? Shrink it right down - you are left with just a hole, and no sleeve.

Then flatten out the curvature of the neck and other parts, and you are left with a flat sheet of clothing, with two holes in it. There is no inside or outside to this, meaning the two sides are interchangeable, and that's why you can turn the real shirt inside out.