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<v ->Well, we're gonna move on now

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and I'm gonna address the presence of intracapsular tendons.

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Now some of you may say, wait, wait,

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tendons don't exist

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within joints, but of course they do,

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and you could think of the biceps brachii about the elbow

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or at the shoulder

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or the popliteus at knee.

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But, you know, there's something very, very interesting

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and people don't realize about intracapsular tendons.

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They traverse a joint.

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They are intracapsular,

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but generally they are extrasynovial.

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Now, if you tell your orthopedic surgeon

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that that biceps you're seeing so well

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with arthroscopy is actually covered by a synovial membrane,

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he or she probably would say, "Well, that can't be.

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"I see it so well, there's no covering,"

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but in fact, in most people,

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the tendon gets into the joint

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by invaginating the synovial membrane.

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And to prove that point,

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if you go in fact to the glenohumeral joint,

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here's the biceps on the image in the center.

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It looks beautiful, it looks like nothing is covering it,

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but as you do an arthogram, look at the image on the right.

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This is a transverse image

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at the level of the distal bicipital groove.

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And these little strands of tissue here

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are in fact the synovial membrane

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that's been invaginated by that biceps tendon.

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So it's in the joint,

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but it is covered by a synovial membrane.

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The other thing that can occur, of course, in pathology

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within the biceps tendon is tendonosis and tendon tearing.

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And I don't wanna show you a lot of cases at this point

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of tendonosis or tendon tearing,

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but I wanted to point out this condition.

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This has a name.

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It's called the hourglass deformity because in fact,

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when you look at the thickened biceps tendon

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within the joint, you can see that's why.

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And it narrows down in the groove,

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and then as you go below the groove,

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you have the myotendinous disjunction, which is wide,

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so it kind of looks like a hourglass.

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Now, when in fact you get extensive thickening

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of the intraarticular portion of the biceps tendon,

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as you elevate your arm,

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the humerus cannot slip over that biceps tendon.

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It's too big.

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And because of that, it becomes entrapped in the joint

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and it invaginates.

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And so here's an example where in fact that had occurred.

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Look at the size in this coronal image

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of that intraarticular portion of the biceps.

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Here it is entering the groove.

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So there's focal thickening of that,

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and here's what it would look like in the sagittal image.

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It's all of this tissue.

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So this is known as the hourglass deformity of the biceps.

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And when you deal with pathology of the biceps tendon,

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as it passes through the joint

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and is intimate with the humeral head,

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changes can occur within the humeral head,

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with tendonosis, with tenosynovitis

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involving it with tendon tears,

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and with it, adhesive capsulitis.

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One can get adhesions between the biceps tendon

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and the humeral head, and one will see these cystic changes.

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They're not specific.

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They're known as a chondral print,

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and I'll talk a bit about them elsewhere in this course,

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but they are something to think about when you see them,

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that there might be an abnormality of that biceps tendon.

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There's another area where you have to study

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the interarticular portion of the biceps tendon

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very closely, and it's at the very top of the groove

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that we know as the pulley.

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Here the biceps tendon begins to extend vertically downward

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into that groove.

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One of the stabilizers of it

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to keep it in the groove is the subscapularis tendon,

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and particularly the upper tendonous portion

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or group one fibers of the subscapularis.

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And what can occur are partial tears or even complete tears

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of that particular portion of the biceps.

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So you have to look very, very carefully

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at the very top of the lesser tuberosity to see the position

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of that biceps tendon.

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And if it is subluxed, that is it is here

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with a bit of it extending over the lesser tuberosity,

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the most likely cause, not the only cause,

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but the most likely cause is a tear involving that distal

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upper tendonous portion of the subscap.

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This is what it would look like arthroscopically,

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the long head of the biceps.

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Here is a subscap showing you an intrasubstance tear

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with medial subluxation of the biceps tendon at the pulley.

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There's another anomaly that you should be aware of

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that involves the biceps tendon

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and it has a very fancy name.

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It's known as the aponeurotic arm of the supraspinatus.

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What it relates to is a band of tissue

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that begins at the supraspinatus myotendinous junction

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and plunges vertically downward and becomes located

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in front of the biceps tendon within the groove.

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Here's what it would look like.

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And as you trace it down, it ends in the area

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of the pectoralis major tendon attachment to the humerus.

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Now this can fool you because as you look at it,

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you see this area of intermediate signal

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between two areas of low signal,

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and you read it as a tear,

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a split there of the biceps tendon.

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But when you deal with split tears of the biceps tendon,

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as shown in this example,

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typically the area of intermediate signal

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is in a vertical position.

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It runs mainly anterior to posterior,

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whereas when you deal with this anomaly,

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the aponeurotic arm, typically you're dealing

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with a horizontal area and interface

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between the aponeurotic arm and the major biceps tendon,

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so you can usually tell them apart.

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The other place we see intracapsular tendons

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of course is in the region of the knee,

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the posterolateral portion of the knee.

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Here the popliteus tendon extends through the knee,

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invaginates the synovial membrane,

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and separates the posterior horn of the lateral meniscus

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from the joint capsule.

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So the lateral meniscus attachments

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consists of strands of tissue

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that pass around that popliteus tendon

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And these strands of tissue

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are known as popliteal meniscal ligaments.

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They're two or three in number

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and this is what they look like.

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And abnormalities can develop within them.

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Here, by the way, is that popliteus tendon.

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You can see it creates a hiatus

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in the area of the popliteal meniscal ligaments

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and then creates an area beneath it

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known as the subpopliteal recess,

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and I'll talk about that recess in a little while

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when we talk about intraarticular bodies of the knee.

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But getting back to these popliteal meniscal ligaments,

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these may be developmentally absent or may be injured.

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And if they're injured, as in this case I'm showing you now,

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then what can occur in certain positions of the knee

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is a dislocation of the posterior horn

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of the lateral meniscus.

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Here at the time of this examination,

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you can see that there is complete disruption

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of the popliteal meniscal ligaments,

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but this patient had been examined one month earlier

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and at that time you can see the posterior horn

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is not located back here.

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It's located adjacent to the anterior horn.

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It had inverted and flipped because of these problems,

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these injuries with the popliteal meniscal ligaments.