Here is a picture of the owner/founder? of North Sea Clothing wearing the Expedition.
Note that the collar is very small. On my sweater, the opening for the head is very small--with the button undone. This is not a sweater that is conducive for wearing a button down shirt underneath. The shawl is very small. It is more like a turtleneck sweater. Putting my (not so big!) head through the sweater opening is like putting on a turtleneck. This picture gives a good idea as to the size of the head opening.
So, wearing a thin, light, long-sleeved layer underneath should be just right. I will post a picture of my sweater, later, when the sun comes up.
This is a perfect sweater for cold weather. Not so much an indoor sweater. (Much like the LL Bean Norwegian. The Norwegian, even in a Small, is HUGE--just the opposite of the Expedition.)