pyramidded shell cross section **GRAPHIC PICS**

[Az tortoise compound]

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I post this here due the conversations it will create.

1. This animal died from "natural" causes. We had a necropsy done by the vet to verify. The shell was returned to us.
2. A hacksaw was used as it was the thinnest bladed saw available.
3. We cut down the middle of the back and cut through the spinal column in the process.
4.I am not a scientist or a veterinarian. I am only attempting to share pics that others might not get to see without this post.

Here goes,

Andy @ A.T.C.
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[moswen]

nice pics. what is the dark stuff inbetween?

[Robert]

Very interesting. What breed and age was this tortoise? Thanks for sharing the pics.

[Balboa]

Thanks Mick! Very Interesting,

Layman Observations , could be way off!

-Looks like the cerebral column was unaffected by the pyramiding. (I've wondered about this before) Now I'm wondering about the bone or cartilage between the shell proper and the spine. Odd looking, but perceptions can be off from a pic.

-The Bone "proper" of the shell directly under the keratin looks pretty good. Seems to be dense and not especially "spongy" like its "supposed to be" (if pyramiding is MBD).

-as previously seen the keratin is relatively thin and follows the bone. It is visibly thicker at its oldest portions.

[moswen]

haha, thanks for putting those observations in an easy-to-understand form for people like myself, balboa! i actually understand most of that except for one thing, where is the cerebral column? i don't believe pyramiding necesarrily equals mbd, though, i think that's what you're saying too?

[Robert]

Interesting. The "spongy" bone looks very similar to our cancellous bone. This is the section of our bone in which marrow is produced and new bone is formed. Also looks similar to our epiphyseal bone found in our "growth plates". The outer, non spongy, bone looks more like our hard cortical bone.

Hard to tell from the pictures, but this also resembles something similar to a fibrous non-union.

What does the "spongy" section feel like? (will be hard to tell unless freshly cut). Does it feel bony like a crouton or fibrous? Sometimes in human bone when a bone breaks we have what is called a fibrous non-union. Instead of healing and building fresh bone at the fracture site, the body produces a fibrous mass which holds the two ends of bone together. This can happen as a result of a number of factors, but in any case it is not good and often requires surgical fixation. I wonder if this spongy section of the scute could be similar to a fibrous non-union? This could be caused by sub-optimal conditions (calcium deficiency, poor humidity, poor nutrition) during growth spurts and could also be caused by rapid growth.

These pictures definitely show why a pyramided tortoise would weigh less than a smooth tortoise. I'm sure that spongy bone is airy and not nearly as dense as the hardened cortical bone.

Really interesting. Thanks.

[Balboa]

(01-17-2011 12:25 PM)moswen Wrote:  haha, thanks for putting those observations in an easy-to-understand form for people like myself, balboa! i actually understand most of that except for one thing, where is the cerebral column? i don't believe pyramiding necesarrily equals mbd, though, i think that's what you're saying too?

I think I had a brain fart and cerebral column isn't a very good word here LOL

If I'm seeing it right, half of the spine is gone, but you can see it on the left. Its cut in half, and you can see where the spinal cord used to be in it.

You're right in that I don't think (for now) that Pyramiding is MBD, I just think they tend to go hand in hand. (a poorly cared for tortoise can very well have both). One is the book, one is the cover. So it is entirely possible to just have one or the other.

In trying to absorb what Andy Highfield is talking about with pyramided tortoises in my layman's mind I recall him talking frequently about "fibrous lesions" or some such, similar to what Rob is talking about above. Very interesting.

In one respect that could be a matter of interpretation then, but I lack the knowledge to judge.

[Madkins007]

It is hard to see the bone structure between the saw cuts, not being a really close-up image, etc., but I also think it looks spongier than it should. Properly developed shell bone should be thin layers of tight structures.

I'm also nervous about that sharp curve inside the shell near the peak- it looks like it it is near a thin section of shell, and like it might have put the spine at some risk. Hind limb problems are fairly common in severe MBD.

Thanks, Moswen!

[Tom]

Great pics Mick.

[moswen]

ugh, it's kind of hard to look at it because you can see like, blood looking stuff and "freshly dead" tissue lol... but i too would like to know what the "spongy looking part" feels like, but i'm SO GLAD i'm not the one touching it!! it might be necessary for you to test it pretty quickly, i think if it will have any give to it it might dry out quickly with it being exposed to the open air.

[Robert]

Radiographs would really be needed to differentiate between spongy cancellous bone and fibrous tissue.

[Az tortoise compound]

I am going to send all my pics to Tom. Maybe he can resize them or display them better than I can. At the time of the photos this male leopard tortoise was dead 24 hrs. From what I see, the bone beneath the scute is solid. It is not porous or spongy like the few other pics I have seen. It isn't completely solid...it kinda looks like maro in the bone but it is hard and does not "give". The cross section isn't perfect due to the friction from the sawblade. To me, it seems to confirm pyramidding without MBD but what do I know?

[Robert]

24 hours would be long enough to make it very hard to assess the rigidity of the "bony" substance. The "give" factor would be gone after that much time. Hard to tell but very, very interesting.

[tortoisenerd]

Is the difference in the density of the pyramids due to the fact that this is a Leopard (naturally pyramids in the wild) vs. another type of pyramided tort like we've seen cross-sections of before? example: http://www.tortoiseforum.org/Thread-Pyra...ne-Disease

[ALDABRAMAN]

Thanks, interesting.