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NBME 23 Answers

nbme23/Block 1/Question#17

A 54-year-old woman comes to the physician because ...

Supraspinatus

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The most important hints to the question are as follows, with #2 being the most specific:

1) patient reports pain with overhead motion and reports recurrent overhead motion during work. Overhead motion can damage the supraspinatus muscle due to impingement by the acromion.

2) Pain is worst with internal rotation of the shoulder - this is consistent with the findings of the empty-can test, which indicates a supraspinatus injury.

mousie  I was thinking along the lines of overhead motion - damage to the subacromial bursa which is between the acromion and the supraspinatus ... also its the most commonly injured rotator cuff m. so could have guessed this one right +1  
sympathetikey  Thanks for the explanation. I was scratching my head as to why this is correct, since supraspinatus only does 15 degrees of abduction, but you make a lot of sense. +1  
charcot_bouchard  IDK WTF i picked Trapezius +11  
ls3076  why would injury to supraspinatus cause weakness with internal rotation though? +5  
targetusmle  yeah coz of that i picked subscapularis +2  
maddy1994  ya the whole question pointed to supraspinatus ...but last line internal rotation made me pick subscapularis +2  
darthskywalker306  I went for Trapezius. That shoulder flexion thing was a big distraction. Silly me. +  




 +1  upvote downvote
submitted by thotcandy(14),

What is there that rules out deltoid? overhead abduction is >15' so shouldn't that point more towards deltoid?

baja_blast  Deltoid only does abduction from 15 to 90 degrees. So not overhead. +  
donttrustmyanswers  With that logic, supraspinatus only does abduction form 0-15 +  




 +1  upvote downvote
submitted by drzed(45),

"During strength testing the patient has pain and weakness with abduction, particularly with simultaneous shoulder internal rotation"

This is a descriptive way of describing Neer's impingement sign, which is a (fairly) specific indicator of shoulder cuff tendon impingement; the most commonly impinged tendon of the rotator cuff being supraspinatus of course.