UWorld Step 1 Qbank: Your world of learning. Subscribe now.

NBME 23 Answers

nbme23/Block 2/Question#47
A 65-year-old man is scheduled for physical ...
Medial (internal) rotation🔍

Login to comment/vote.

 +10  upvote downvote
submitted by guillo12(36),

The subscapularis muscle is very important for the Internal rotation of the humerus. The internal rotation supports the upper arm during abduction and adduction.

There are some band exercises that can help you strength the Subscapularis muscle... 1. Internal Rotation - uses medial internal rotation 2. External Rotation - uses lateral external rotation 3. Front Row - You have you hand up in front of you and with your arm extended pull back the band. 4. Side Row - You're side to the band with your hand facing the hip, pull down toward your body. (ADDUCTION)


arcanumm  I got this wrong too, but I think the exercise of internal rotation makes sense because it will isolate the muscle (without assistance by teres minor for adduction). +4  
tiredofstudying  The subscapularis assists in medial (internal) rotation and adduction, but the teres minor also assists in adduction, so the best choice to isolate the subscapularis would be internal (medial) rotation. Choice E +  
thotcandy  @tiredofstudying teres major also internally rotates so it wouldn't really be isolated either. I guess Tmajor isn't relevant cuz it's not a SITS muscle? Still a stupid question. +  

 +1  upvote downvote
submitted by nicsar(1),

a)abduction: supraspinatus-deltoid-triceps-serratus anterior

b)adduction: subscapularis-pectoralis major-lattisimus dorsi- teres major

c)extension=horizontal abduction; post. deltoid, infraspinatus, teres minor

d)internal rotation: subscapularis

for isolated work out, d is better.


thotcandy  teres major also internally rotates? It's attached to the medial lip of the humerus +1  
neovanilla  teres minor externally rotates (+ad-duction) +  

What puts internal rotation over adduction? Subscapularis muscle does both

smc213  probably because the subscapularis m. is the only SITS muscle that does internal rotation & adduction along with the teres minor m. action being adduction & external rotation. +1  

Shoulder muscles that form the rotator cuff: Supraspinatus (suprascapular nerve)— abducts arm initially (before the action of the deltoid); most common rotator cuff injury (trauma or degeneration and impingement; tendinopathy or tear [arrow in A ]), assessed by “empty/full can” test

Infraspinatus (suprascapular nerve)—externally rotates arm; pitching injury

teres minor (axillary nerve)—adducts and externally rotates arm

Subscapularis (upper and lower subscapular nerves)—internally rotates and adducts arm

UWorld Step 1 Qbank: Your world of learning. Subscribe now.