# pyramidded shell cross section **GRAPHIC PICS**



## Az tortoise compound (Jan 17, 2011)

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,


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## moswen (Jan 17, 2011)

nice pics. what is the dark stuff inbetween?


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## Robert (Jan 17, 2011)

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


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## Balboa (Jan 17, 2011)

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.


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## moswen (Jan 17, 2011)

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?


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## Robert (Jan 17, 2011)

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.


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## Balboa (Jan 17, 2011)

moswen said:


> 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.


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## Madkins007 (Jan 17, 2011)

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!


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## Tom (Jan 17, 2011)

Great pics Mick.


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## moswen (Jan 17, 2011)

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.


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## Robert (Jan 17, 2011)

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


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## Az tortoise compound (Jan 17, 2011)

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?


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## Robert (Jan 17, 2011)

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.


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## tortoisenerd (Jan 17, 2011)

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-Pyramiding-in-tortoises-with-Metabolic-Bone-Disease


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## ALDABRAMAN (Jan 17, 2011)

Thanks, interesting.


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## Madkins007 (Jan 18, 2011)

Az tortoise compound said:


> 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?



Spongy bone does not automatically mean soft. It is just a way to describe bone that is open and porous, like marrow, compared to the tight, laminated bone it should be.





is spongy bone- this is naturally and properly spongy marrow bone, but it shows the idea. 

Here is a photograph of naturally and normally spongy bone:





It is harder to find good proper bone examples, but here are a couple:





This is a skull, which structurally is similar to a shell. Notice that there are no dark areas in the hard, tight bone:





As gross as it sounds, the best way to see if the shell in the original photos is spongy or not is to smooth one of the surfaces and get a good look with a magnifying glass. Because all bone is porous to a degree, some pitting should be seen no matter what, but sponginess will look like a close-up of a natural sponge.


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## Robert (Jan 18, 2011)

I always compare spongy, cancellous bone to a crouton that you would find in a salad. It is hard and crunchy, not soft. Looks like a sponge but feels like a crouton. The diagrams above are perfect. 

The reason that I asked if it felt soft was because I am interested to see if that space is filled with fibrous tissue and not spongy bone. We see this in bony fractures sometimes. It can be caused by a number of factors. I'm intrigued by the fact that Balboa mentions an earlier reference to fibrous tissue. Balboa: do you have a link to those studies by any chance?

Just a thought: if the bone is growing rapidly, possibly because a tortoise is eating more than they would in the wild, and all environmental factors are not present to support rapid bone growth, then this formation of fibrous tissue would make sense. 

I'd be interested to see what the effects of humidity have upon the torts ability to properly regulate calcium uptake. Dehydration will alter the ph level of blood. To offset this, blood will resorb calcium from bones. If this is happening during rapid bone growth, then something (fibrous non bony tissue) must fill the gap if the proper calcium needed for bone formation is not present. This may explain why thoughts about rapid growth and humidity both seem to play a role in pyramiding. I think there might be something to this, but I don't have the means to study it directly. I'll do some more digging and try to find some links between dehydration and proper bone formation.


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## Balboa (Jan 18, 2011)

Welcome to the fascinating, frustrating, regurgitating, never-ending debate on pyramiding 

Many folks are sick of it, others never get tired of discussing it.

As you seem to have some professional background, who knows, maybe you'll be able to shed some new light.

You can read Andy Highfield's latest presentation on the subject here
http://www.tortoisetrust.org/articles/pyramiding.html
And a little more info about the "fibrous" subject on another forum here 
http://www.reptileforums.co.uk/foru...toise/106535-pyramiding-misinformation-5.html
Andy's username there is "tortoise trust"
The best discussions I've read were unfortunately on a forum that I cannot link nor reproduce here, sorry.

A warning on Andy's work and opinions though, he's very strong willed and set in his opinions and IMHO skews and denies the excellent science and the data in his presentations. His passion and brilliance are however undeniable. I find the best answers to my questions in what he denies about what he's discovered 


If I'm reading Mark right, I agree, there are some disconcerting "weak spots" in Mick's carapace that could pose real threats to a tortoises well-being. Whereas the half-sphere shape of a "healthy" tortoise is very strong with even loading of applied pressure, the pyramid structures in the above carapace will create stress points at the thin bone where they join. (If those words portray my thoughts correctly  )


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