July 24, 2007

Pathology Tuesday

Today I took this picture of three thoracic vertebrae. Normal degenerative changes in the spine appear as osteophytes - little spicules of bone that protrude horizontally from the body of a vertebra. In this person's mid-back, however, there was excessive bone formation vertically, causing at least two of the vertebrae to fuse together. This condition is known as ankylosing spondylitis (or ankylosis for short). It most commonly affects the vertebral joints and the sacroiliac joint (where your hips join your sacrum in the back), and it limits the range of motion that an individual can engage in. In the case pictured, one of the vertebral discs (an area of articular cartilage) was partially or wholly destroyed during life. To cope with the loss of mobility, the body created syndesmophytes - basically, ligaments that ran vertically and originally helped stabilize the spine were converted into bone. At the top of the photo, you can see that a third vertebra has developed syndesmophytes, but these have not fused to the vertebra beneath it yet. For unknown reasons, ankylosing spondylitis appears to affect males more than females, nearly 3 to 1, and begins to affect the joints after a person reaches 30. It is a progressive disease, and there are archaeological examples that show entire spines fusing together. Unfortunately, I only had a few vertebrae from this individual, so I could not document the extent of spinal fusion for this particular person.

5 comments:

Lara said...

Hmm, was this the same condition that I tried to convince you was present on my skeleton?

Kristina said...

I believe your skeleton had DISH - diffuse idiopathic skeletal hyperostosis. DISH affects not only the spine but also elements like the bones that make up the ankle, elbow, and hip joints. DISH looks almost like candlewax poured down the spine. The picture I posted here is definitely ankylosis, which starts off in isolated places and then affects the whole spine and sacrum. But it doesn't seem to affect the rest of the body.

Lara said...

Are they kind of the same thing except that DISH can affect other parts too whereas ankylosis doesn't?

American Nationalist said...

So does this mean they were doing a lot of stoop work or something to wear out the cartilege? Or is this more of something genetic? Because if it's from wear and tear, I could see how archaeological examples of it would be largely men in many populations.

Anonymous said...

AS is genetic. Majority of persons with it have genetic marker HLAB27.

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