NBME 23 Supraspinatus (NBME Answers)

NBME 23 Answers

nbme23/Block 1/Question#17 (reveal difficulty score)
A 54-year-old woman comes to the physician ...
Supraspinatus 🔍 / 📺 / 🌳 / 📖
tags: anatomy repeat

+11 upvote downvote
submitted by ∗thomasalterman(181)

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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.

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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 +2

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 +46

ls3076 why would injury to supraspinatus cause weakness with internal rotation though? +9

targetusmle yeah coz of that i picked subscapularis +3

maddy1994 ya the whole question pointed to supraspinatus ...but last line internal rotation made me pick subscapularis +3

darthskywalker306 I went for Trapezius. That shoulder flexion thing was a big distraction. Silly me. +1

lowyield saw someone post this on one of the other questions about shoulder... and it works pretty good for this https://www.amboss.com/us/knowledge/Soft_tissue_lesions_of_the_shoulder there's some videos in it, this specific one for the question is the neer test +

psay1 FA2019 pg. 438 +1

hookofhamate for those who got confused w/ internal rotation - im pretty sure what the last line (pain and weakness with abduction, esp with internal rotation) is describing is the empty can test, which is basically only for supraspinatus injuries because that motion of your arm traps the supraspinatus tendon against the humerus head and causes pain (someone correct me if im wrong pls) but yea, i only figured it out because i had to do the motion with my arm +

zasachwa For anyone confused about why Supraspinatus since it abducts 0-15, and why Empty/Full can test actually tests the Supraspinatus heres a video: https://www.youtube.com/watch?v=r1bnUcjytXk +

zasachwa Basically, "internal rotation of the arm decreases the effect of the deltoid muscle on abduction and allows isolated examination of the supraspinatus muscle" +

+4 upvote downvote
submitted by ∗skonys(58)

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"I do not know who I am. I do not know why I am here. All I know is rotator cuff anatomy" ~ The Writer of this Exam (probably)

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+3 upvote downvote
submitted by ∗drzed(332)

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"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.

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+1 upvote downvote
submitted by ∗thotcandy(131)

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

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baja_blast Deltoid only does abduction from 15 to 90 degrees. So not overhead. +1

donttrustmyanswers With that logic, supraspinatus only does abduction form 0-15 +10

rina the positive empty can test is the biggest thing "pain and weakness with abduction, particularly with simultaneous shoulder internal rotation" - that tells you it has to be one of the SITS muscles (supraspinatus, infraspinatus, teres minor, subscapularis), not the deltoid. tenderness in the right deltoid region tells you it's the supraspinatus which is right underneath the deltoid muscle +2

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