To be honest- I just took (and rocked) the anatomy shelf exam, and think that BRS is overkill. Seriously. BRS questions are WAAAAAY harder than the shelf.
I got some good advice browsing around these forums that I would pass on- know collateral circulation paths, abdominal stuff, and take a good look at the uterus/ovaries (a few hysterectomy questions and they LOVE ectopic pregnancy, and don't forget "water under the bridge" for the ureter running under the artery) and know testicles/male reproductive stuff too (there were a good 5 questions on this stuff, should have taken a better look at it).
Very little head and neck (even though this was what was freshest in my mind). A decent amount of muscle/innervation stuff, but nothing super complicated. Refresh yourself on brachial plexus, but don't freak out over it.
Honestly- I thought my best preparation came from knowing the U Mich questions. When I was taking the exam, it felt like 50% of them came right out of U Mich. There was ONE question on the whole exam I had never heard of/seen before. The rest of them I could answer in 2 seconds, or I could narrow down to 2 answer choices, and the only reason I didn't know it because I was too lazy to review some of the sections on U Mich (ie. the fingers/hands- one or two questions on that?)
BRS is way too in depth and the questions are super hard- the shelf is nowhere close to being so complicated.
Just my two cents...