Whats the difference between sleeping this way on pillows or sleeping flat on the bed? The only difference i can tell from the diagrams is that is changes the curve in the thoracic spine. i'll still give it a go though, I'll try anything. I sleep with my arms straight and externally rotated. This position feels good for my TOS but sleeping on ones back isn't very comfortable (though i find it impossible to sleep on my side without being woke up by a dead arm). Also are your elbows bent in the picture ? 40% of people with TOS are supposed to have signs of peripheral nerve entrapment as well so it may not be a good position for everyone eg.if you have ulna nerve entrapment at the elbow

Thanks for the above article. Will give the exercises a try