Thoracic Outlet Syndrome - Fact or Fiction?

Jon writes in response to this:

As a 3rd year clinical student, i look back at your questions and go...damn, this stuff is hard. this is probably bc nobody in clinical years go in detail about which pleura you are in. Sir your buck's fascia is torn....yea like the patient knows or cares that it was torn. all he knows is that something's torn and can you fix it lol. The boards dont even go into this much detail.
So i got my scores for USMLE STEP 1 back, I passed. But I couldnt tell you what thoracic outlet syndrome is.... lol

So it got me thinking; what kind of yield does Thoracic Outlet Syndrome have on the Step?  My guess would be 'very little' but it sounds like it may be 'none at all'.  (And maybe they just teach different things at different schools?)

(Also, unanswered questions bug me.)

According to BRS Anatomy, Thoracic Outlet Syndrome is defined as the compression of the neurovascular structures between the clavical and first rib, causing a combination of pain, numbness, tingling, and weakness.  In my practice question, I state that the ulnar n., median n., and subclavian a. are all affected by Thoracic Outlet Syndrome.  BRS Anatomy is close.  They cite the subclavian a. specifically, but then go on and only talk about the C8 and T1 spinal nerves.

In the power point slides here at Ross, the structures that are affected are clearly labeled and explicitly stated.  The specific nerves are singled out instead of the nerve roots.  So far so good, right?

Then First Aid 2010 mucks it all up.

In First Aid, Thoracic Outlet Syndrome is under the heading, "Klumpke's Palsy and Thoracic Outlet Syndrome" and tags it as an "embryologic or childbirth defect affecting inferior trunk of brachial plexus."  Below that on the same page, the next section describes distortions of the hand.  One of those distortions is "Klumpke's Total Claw" which is defined as a lesion of C8 & T1.  It says nothing about the thoracic outlet, but describes the same symptoms.

I forgot to mention that in my lectures, unlike BRS Anatomy, Thoracic Outlet Syndrome mentions nothing about the "clavical and first rib."  It's only described as the superior opening of the thoracic cavity.

I'm so confused.

In conclusion, Thoracic Outlet Syndrome may or may not be defined as the compression of neurovascular structures out of the superior thoracic cavity and/or between the clavical & first rib.  The structures that are affected include the subclavian artery and spinal nerves T8 & T1 which may or may not be limited to the ulnar and median nerves.  Thoracic Outlet Syndrome may or may not also be referring to an embryologic or childbirth defect affecting the inferior trunk of the brachial plexus.  It also may or may not also present with the same symptoms of Klumpke's Total Claw.

Q: Thoracic Outlet Syndrome?
A: Fact-ish.


(In conclusion of the conclusion: As with everything in med school, learn whatever you're taught in class because that's what you're going to be tested on.  Later on when studying for the Step, when all else fails, go with First Aid. This is the only source that matters in the end.)