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<v ->Okay, we're gonna go ahead and continue now

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after the break.

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And we begin our discussion of some specific disorders.

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We'll be continuing that discussion

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over the next two sessions as well,

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but I think it's entirely appropriate

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we begin with two of the most common disorders

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that we deal with, and that is rheumatoid arthritis,

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and the somewhat similar spondyloarthropathies.

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These are some drawings they made years ago

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to kinda compare the pathology of rheumatoid arthritis

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on the left, with that of spondyloarthropathy,

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often abbreviated now, SPA or SPA, on the right.

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And there are many similarities between the two

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as you look at these drawings.

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I'm gonna point out a couple of similarities,

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but also some differences.

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Typically, in rheumatoid,

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we think of an early process of synovial inflammation

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associated with joint the effusion,

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capsular distention, and eventually,

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the presence of marginal erosions,

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intraosseous extension of panus and fibrous ankylosis.

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That's classically what we think of

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when dealing with rheumatoid arthritis.

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Some of the same similar findings can be appreciated

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in the spondyloarthropathies, including synovitis,

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an enlarging joint effusion, capsular distension,

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and erosions extending into the subchondral bone.

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But there are two particular findings that may be different,

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and it's those findings,

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even when examined with conventional radiography,

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that can help you differentiate between these two disorders.

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The first of these is bone proliferation,

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and we'll be talking about that in some detail.

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The counterpart with MR imaging is marrow edema,

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so the two seem to go together.

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There are several reasons why we get bone proliferation.

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We often use the term whiskering to describe its morphology,

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but we'll get into that a little bit

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with some of the following slides.

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And then the second difference may be a higher frequency

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of intraarticular bone fusion,

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particularly at certain sites.

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For example, we can think of the sacroiliac joint

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and certainly, in some instances,

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of disease involving the sacroiliac joint

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with ankylosing spondylitis,

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or even with psoriasis, intraarticular bone,

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ankylosis may occur.

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So we can look at conventional radiographs

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and you're gonna see these two images

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once more during my lecture,

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but here we have rheumatoid arthritis on the left,

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and we have the spondylopathy,

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in this case, psoriatic change, on the right.

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And you can appreciate, with rheumatoid arthritis,

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we deal with marginal erosions,

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we deal with joint space loss,

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we deal with soft tissue swelling,

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and periarticular osteopenia.

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The degree of osteopenia can be less

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when dealing with the spondyloarthropathies,

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but the main difference I wanna point out

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is this pattern of bone proliferation.

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And a lot of it, producing what we know as whiskering,

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occur where the capsule, as we just were talking about

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with Carlos, where the capsule attaches to bone,

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that there may be areas of bone proliferation.

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This is the most important morphologic feature

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that separates the spondyloarthropathies from rheumatoid.