0:00

Okay, let's talk about some anatomy in the axial projection.

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We're going to begin up high.

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Here's the coracoid as a landmark.

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And as we scroll, one of the easiest

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structures to identify is the biceps long head.

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In the bicipital groove, you should be looking at the

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bicipital groove, shape, its depth, its smoothness,

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and the medial and lateral walls of the biceps.

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The biceps is secured by the transverse ligament.

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Which is formed by the coracohumeral ligament,

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which we'll discuss in detail in a few moments.

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But this biceps pulley mechanism complex

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consists of a medial and a lateral component.

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The lateral component inserting on the greater tuberosity.

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The medial component inserting on the lesser tuberosity

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receiving contributions from the subscapularis.

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And even the pectoralis major tendon, but mostly

0:53

from the coracohumeral ligament from the coracoid.

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Now let's get up a little bit higher for a minute.

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I'm gonna scroll up approximately, or craniad.

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When I get up craniad, I see this structure right here.

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Uh, the elusive superior glenohumeral ligament.

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We see it so well because we have an MR

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Arthrogram on a T1 and a fat-suppressed

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image, also with the joint distended with fluid.

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Now, one noteworthy aspect of the SGHL, which arises from

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the superior glenoid tubercle anterior to the biceps.

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And when I say anterior to the biceps,

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I'll show you the biceps right there.

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And then the structure is anterior to

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it, but they tend to parallel each other.

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So the SGHL comes out and around,

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above and in front of the biceps, and

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then as we get out laterally, you're going

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to see that it'll curl under the biceps.

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That's not easily appreciated in this projection.

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Now some of you are wondering, what's this sheet right here?

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That sheet is fibroelastic tissue that

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comes back from the coracohumeral ligament.

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And some people have even referred to it as the

1:58

superior CHL or the superior intra-articular CHL.

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And it's often, as you can see, right next

2:07

to the SGHL, and sometimes confused for it.

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We'll talk about the function of the SGHL

2:14

a little bit later when we speak about

2:15

biomechanics, but I wanted you to see it.

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Let's work our way down a little more inferiorly to

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the region of the MGHL, and again we're going to talk

2:24

about biomechanics a little later, but the easiest

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way to identify the MGHL is to find the subscapularis.

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The MGHL course is right behind the subscapularis.

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It parallels it, and it inserts on the

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middle facet of the lesser tuberosity.

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Now sometimes it'll have a little loop associated

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with it, or it'll have an extra fascicle,

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and an extra band, and this band is sometimes

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referred to as the lamina propria.

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And it'll come up obliquely from the bottom

2:57

superior, or maybe directly horizontally oriented.

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The insertion of the MGHL on the middle facet

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is seen here, deep to the subscapularis.

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Now one easy way to identify the MGHL, which

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is sitting directly behind the subscapularis

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and hugging it, so sometimes it's a little hard

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to identify, and separated from the IGHL as we

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go down, is the IGHL has more of an arc to it.

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So here is the arc shape of the IGHL.

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So here you've got MGHL coming down

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straight, straight, straight, straight.

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And now all of a sudden we transition

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to the IGHL, immediately on one cut.

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MGHL, IGHL.

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So the IGHL is now curving anteriorly.

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And it's actually bifurcating into a couple of bands.

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These are both anterior bands.

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It's not uncommon to see bands or syneciae in the front.

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And the IGHL, all the way at the bottom,

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is going to have an axillary band.

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And in the back, it's going to have a posterior band.

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You'll see later on that the IGHL is the most

4:00

important stabilizer in individuals who are in

4:03

the extreme abduction external rotation position.

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And when you're in this position with your arm up and back,

4:10

this area is a source of restraint and it's very taut.

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Most people don't actually dislocate in this

4:17

position when they are recurrent dislocators.

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We'll see later on they dislocate in

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what I call the mid-shoulder position.

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And that'll be a discussion for another day.

4:26

So my purpose here was just to introduce you

4:28

to the three major glenohumeral ligaments.

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The SGHL up top, the MGHL in the middle,

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traveling with the subscapularis.

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The SGHL travels with the biceps.

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And then the IGHL,

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which has three major bands, and sometimes

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some minor bundles anteriorly, an

4:47

anterior, an axillary, and a posterior.

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Let's move on, shall we?