Case of the Conjoined Fingers

I worked a solid ten-hour day today, which is not horrible. But toward the end of it, I was not feeling like Someone Who Plays the Violin and Practices Regularly. I was feeling like Someone Who Just Had a Long Day and Wants to Eat Dinner and Then Veg on the Couch. However, when I did wrap up the work day, it actually felt great to set up my stand, open up the case, attach the shoulder rest, and move on to something completely different. 

I've been working on a double-stop exercise that includes several measures like this:

Looks fairly tame, eh? But when I play it, my first and second fingers end up conjoined at the second knuckle. I blithely practiced two or three lines of this stuff before my last lesson without really being aware of this. At my lesson, Ms. L pointed it out and was trying to get me to bring my hand further under the neck to unstick my fingers. That still didn't seem to do it. I felt like my hand was just at the wrong angle to the neck or something. I just could not figure out how to move my second finger up and down without it ending up crunched up against the first. It was as though I had never moved those fingers independently of each other before.

In my practicing so far this week, it hasn't gotten much better. Today I just started reaching my hand under the neck at what feels like a ridiculous angle. I think it worked a little bit better despite the feeling of ridiculousness. Maybe it's just one of those weird adjustments I have to get used to. I have my next lesson on Saturday instead of Friday, so I have two more days to experiment with it.