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<v ->We're gonna finish up around talking about

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some of the complications that involve rheumatoid

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and the spondyloarthropathies.

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The first of these we've talked about earlier

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and that is synovial cyst.

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And I'll remind you the definition of a synovial cyst

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is a fluid collection

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that communicates directly with the joint lumen.

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This is an old case

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of patient with rheumatoid arthritis

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of the glenohumeral joint.

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It was interesting

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because of the size of this synovial cyst,

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which was communicating with the joint lumen

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extending far down.

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It looks like having, not just synovial proliferation

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perhaps early rice body formation and the enhancement

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of that cyst and of the synovium in the joint

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in this patient with rheumatoid.

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We talked about bursitis and certainly patients

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with rheumatoid arthritis can develop bursitis.

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Here are examples of intermetatarsal bursitis

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associated with joint disease and bone erosions as well.

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And let me remind you again

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that perhaps the earliest erosion of rheumatoid arthritis

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in the entire skeleton is the lateral aspect

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of the fifth metatarsal head.

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Unfortunately, it's not a specific finding

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but it is a sensitive finding, an early finding.

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Now, one of the other complications

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I'm gonna spend a moment on this is malalignment.

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We certainly recognize this in rheumatoid arthritis

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and we recognize the involvement of the C1, C2 articulation.

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So let's spend a moment learning about the anatomy up here.

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This is my drawing of a sagittal look

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at the anterior arch of C1 and the C2,

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including the odontoid process.

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And if you look at this,

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indeed what you can see here

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is that there are two synovial joints.

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They have fancy names.

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They're known as the anterior

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and posterior median atlantoaxial joints.

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They generally do not communicate.

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They probably do with rare, rarely

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but I've never seen them communicate

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but these are synovial joints

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bathing the front and the back of the odontoid process.

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This is the transverse ligament

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of the atlas that swings around the odontoid process

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attaching to the anterior arch of C1.

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The major findings that we see at C1 and C2

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and rheumatoid arthritis are subluxation and bone erosion.

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We can understand the bone erosions

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because of the synovitis

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within these median atlantoaxial joints.

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We can understand subluxation

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because of the hyperemia

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associated with the synovitis producing ligament laxity.

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The subluxations can be either horizontal

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or they can be vertical.

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And so let me explain why both, there are two patterns.

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The pattern you know the most of about

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is the horizontal pattern transverse in nature.

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You can appreciate it

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when the patient flexes his or her neck

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by measuring the distance

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between the back of the anterior arch of C1

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and the odontoid process here.

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There are some measurements in the literature.

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There's a little bit of variation

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about what is considered normal in adults and in children.

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In the neutral position

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and certainly in the extended position,

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that will not be seen, all right?

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This is the more frequent pattern of malalignment.

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It is less neurologically significant

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than the vertical pattern.

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So here is an example of the vertical pattern

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and what that means is the cranium and C1

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settle on the odontoid process.

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So here, part of the cranium,

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here is the anterior arch of C1.

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It's moved down.

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It's not articulating up here,

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but it's at the lower part of the odontoid process.

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Now you come along as the imagers, you look at this image,

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you look at it too quickly and you say, well

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we're dealing here with some anterior subluxation, okay?

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I recognize that, I'm not gonna worry too much

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about it at this stage.

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The patient comes back three years later

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and this is what you have.

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And you first look at it quickly.

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Again, you say things are better

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because the anterior arch is closer to the odontoid process.

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But the reason it is,

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is is articulating even lower down on the odontoid.

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So look at what's happened to the odontoid process

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passing through the foramen magnum.

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Less frequent, more neurologically important,

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and it relates to joint disease

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and the lateral joints between the occiput and C2

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with collapse of the lateral masses of C1.

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We call this cranial settling

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'cause it's the cranium and C1 that settle on C2.

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The third pattern of subluxation

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is really a little bit different.

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It's called lateral head tilt,

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and it relates to the fact

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there may be asymmetrical involvement

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of the lateral masses that head tilts toward the side

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of more extensive involvement and rotates the opposite side.

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So this is called lateral head tilt

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in patients with rheumatoid arthritis.

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Periarticular injury occurs in rheumatoid.

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I showed you this slide before,

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and when we were talking about septic arthritis,

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but indicated it was a case of rheumatoid

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with rapid loss of joint space.

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Now, if you look at the specimen first,

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here is a portion of the rotator cuff,

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this is the supraspinatus.

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This is the pannus in the joint in a cadaver,

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and you can see why that pannus may attack

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the rotator cuff tendons.

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So disruption of the rotator cuff tendons

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in patients who have glenohumeral joint synovitis

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can occur, all right?

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And therefore that does occur in rheumatoid.

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Note the narrowing of the acromiohumeral distance.

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Now there's another interesting thing here.

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Because of the disruption of the rotator cuff tendon,

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pannus can extend from the glenohumeral joint

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into the subacromial-subdeltoid bursa

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and then can extend into the acromioclavicular joint.

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So it's polyarticular, but it began as disease

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in a single joint that moved into a second joint.

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The same thing can occur in septic arthritis.

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Here, again, rheumatoid chronic disruption

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of the rotator cuff tendons,

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communication of the joint

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with the subacromial-subdeltoid bursa.

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And sometimes the cuff tears abruptly, all right?

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And can lead to the sun onset

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of increased pain in the shoulder.

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Now, other tendons may tear in rheumatoid arthritis,

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the flexor carpi radialis tendon may tear.

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I talked about that early on.

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I indicated it's intimate with the triscaphe joint.

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So it may tear with OA

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but it also can tear with rheumatoid arthritis.

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Complete tears of this tendon are pretty common.

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And in fact, many of the tendon tears in rheumatoid

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dominate in the hand and wrist.

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The soft tissue nodules of rheumatoid arthritis

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are not specific when evaluated with MR.

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Low signal on T1, inhomogeneous signal on T2

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and also inhomogeneous enhancement is characteristic.

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Here's a rheumatoid nodule.

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Here's another example of a rheumatoid nodule.

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We can have spinal cord compressions.

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Clearly remember in rheumatoid,

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we get the step ladder appearance often

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in the cervical spine with multiple subluxations.

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In this case, it's subluxation mainly

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at one level looks like C5, C6 with spinal cord involvement.

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Rheumatoid arthritis is the most common cause

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of polyarticular septic arthritis.

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It is very difficult clinically

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in a patient with rheumatoid to suggest, wait a minute.

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Now I think that joint also is infected

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because the clinical findings

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look like an exacerbation of rheumatoid arthritis.

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So sometimes there are some features on the MR

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or on the plane film that will help you

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but often there are not.

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So it depends on clinical suspicion

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that they had an aspiration.

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This case is rheumatoid and septic arthritis

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involving the compartments of the wrist.

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And finally, as I talked about

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rheumatoid of the sacroiliac joints

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is infrequent, all right?

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We don't see it that often.

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So if a patient with rheumatoid has back pain,

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it's better to think of insufficiency fractures

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involving the bones of the pelvis.

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And although those insufficiency fractures can occur

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in the ileum and the pubic rami

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and in the parasymphyseal bone.

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And I'm gonna show you examples

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I think on Sunday of some of those.

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The most characteristic location is the sacrum.

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And typically there are vertical fracture lines

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and horizontal fracture lines

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creating what's called the Honda or H sign

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on the radionuclide study.

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Often they are obscured with conventional radiography

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because of gas and soft tissues.

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CT is a terrific technique for finding them.

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MR can also show you the edema.

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Sometimes the fracture lines, as in this case,

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note the distribution close to the sacroiliac joint.

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So that's a characteristic.

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Here's another example, old case.

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You can see this sclerosis on the plain film.

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You can see the changes in marrow signal.

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It's hard to see the fractured line on the MR.

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And then of course you can get insufficiency fractures

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in other bones, more often

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in the lower extremity than in the upper extremity

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in patients with rheumatoid arthritis.

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And this is part of the topic

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we'll be talking about on Sunday.

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So with that said,

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I've come to the end of my last segment here,

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and we're gonna once again, turn to Carlos

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to talk about some cases related to some of these findings.