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I'm going to share with you now the passive and the

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dynamic stabilizers of the shoulder in the coronal

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projection with a reference axial projection,

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arthrographically enhanced, um, on the left hand side.

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So let's start scrolling the coronal

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projection, and let's start easy.

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Easy is the supraspinatus and its tendon.

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That is one of the dynamic stabilizers.

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So the rotator cuff is a dynamic stabilizer.

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And part of the rotator cuff, besides the

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supraspinatus, infraspinatus, teres, and

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subscapularis, and capsule, is the biceps.

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So let's see if we can locate the biceps.

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There it is.

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And the biceps courses over the top of the humeral

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head and contributes to humeral head depression.

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In other words, it keeps the humeral head from floating up.

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So it's an oft overlooked, uh, Dynamic stabilizer.

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Some other dynamic stabilizers we're

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not going to show you right now.

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The pectoralis major, the latissimus, periscapular

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muscles, and some other muscular structures.

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Let's focus on the passive stabilizers.

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These include the glenoid rim, the glenoid fossa,

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the labrum, and the capsuloligamentous structures.

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And it's the capsuloligamentous structures

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that I want to focus on right now.

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And specifically, the most important of them all, the

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granddaddy of them all, the inferior glenohumeral ligament,

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which merges imperceptibly with the inferior labrum,

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and that's why we call it a labroligamentous complex.

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I defy you at this mid-coronal plane, where we have the

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axillary band of the IGHL, and yes, there are three bands.

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I defy you to tell me where the

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labrum stops and the ligament begins.

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You can't.

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And sometimes it'll break here, but

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most of the time it comes off here.

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So this whole structure will come off and be

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yanked downward in various types of dislocation.

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And sometimes this axillary band will plastically

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deform and become droopy and too big to move.

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Too low and too wide.

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Now a more critical structure, and by the way, before I get

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to that critical structure, look at that tight insertion

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on the humeral neck, the axillary band of the IGHL.

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Let's go backwards just for a minute.

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You can see that insertion a little more wispy, and when

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you get a vulsion back here, this is called a reverse hagel

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or reverse humeral avulsion of the glenohumeral ligament.

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I defy you again to determine the IGHL.

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Differentiation of the labrum from the IGHL.

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Where does one stop and the other begin?

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Where is the transition zone?

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Once again, a labral-ligamentous complex.

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And yes, there is a little more laxity in the back to allow

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for plasticity with the overhead throwing-type motion.

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And the more you throw, the more plastically

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deformed this will get physiologically.

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But sometimes, it's not.

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Now let's go forward to the anterior band

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of the inferior glenohumeral ligament.

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It's a big, thick structure and it too

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has an insertion on the humeral neck.

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Once again, difficult to tease out or separate out

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the labro-ligamentous interface for they are one.

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And the site of potential weakness

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or breakage is difficult to ascertain.

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But the insertion on the humeral neck is

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easy to see, a tear at this location, or an

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avulsion here, would be known as a haggle.

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A humeral avulsion of the glenohumeral ligament.

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You take a piece of bone, it's called

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a behaggle, a bagel, or a bony haggle.

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We'll talk about the other variations of interruption and

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injury of the inferior labral-ligamentous complex here,

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here, and here, as they have a few other interesting names.

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But that's a story for another day.

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Let's go upstairs to the superior glenohumeral ligament.

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Which is coming straight at you.

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Right?

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Look at it axially.

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Let's go up high.

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It's coming at you.

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And that's why it's difficult to see.

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It's right there and there.

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And then it's crossing over, paralleling the

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arc or orientation of the biceps long head.

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Now we've got a series of parallel structures.

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One of which is the biceps.

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But what's this?

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The CHL, the extraarticular CHL, the coracohumeral

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ligament, which forms the deepest layer of the rotator cuff.

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So, oh, so many linear structures paralleling one another.

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The CHL, the biceps long head, and even

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the supraspinatus is paralleling them all.

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And sometimes you'll even see, as we do in this case,

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a parallel, slightly oblique, parallel S, G, H, L.

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Now let's talk about the CHL for a moment.

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It's a pretty thin structure.

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It attaches to the undersurface of

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the supraspinatus as we see here.

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It forms its deepest layer.

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It also attaches to the lesser tuberosity and greater

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tuberosity as it forms the transverse ligament and it's

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also the anterior boundary of the rotator interval.

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Here it is right here.

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It takes off from the coracoid and

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extends over toward the humerus.

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Where it will form the upper portion of the capsule

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and then descend as the transverse ligament.

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Let's see it descend as the transverse ligament,

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helping to secure the biceps long head with greater

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and lesser tuberosity insertion inflection points.

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That is a discussion of the passive and dynamic

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stabilizers of the shoulder in the coronal projection.

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Let's move on, shall we?