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On the Fifth Day of Freezermas, this blog gave to thee…

February 15, 2013 by John of the Freezers

…a daily picture of anatomy! And today it is five pictures; zza-zza-zee! ♫

Welcome back again, again, (gasp, pant) and again to Freezermas! 

I’m letting the dogs out today. Science gone barking mad! Hopefully my puns will not screw the pooch.

Stomach-Churning Rating: 4/10; a dog cadaver’s leg (not messy), then just tame digital images of anatomy.

I am working with Rich Ellis, a former MSc student at Univ. Colorado (see his cool new paper here!), for a fun new collaboration this year. He was awarded a prestigious Whitaker Foundation scholarship to do this research, which focuses on how different animals stand up from a squatting position, with the legs about as bent as they can be.

We want to know how animals do this standing up movement, because it is in some ways a very demanding activity. Very flexed/bent limb joints mean that the muscles (and some tendons) are stretched about as far as they ever will be. So this places them at disadvantageous lengths (and leverage, or mechanical advantage) for producing force. We know almost nothing about how any animal, even humans, does this-– how close to their limits of length are their muscles? Which muscles are closest? Does this change in animals with different numbers of legs, postures, anatomy, size, etc? Such fundamental questions are totally unaddressed. It’s an exciting area to blaze a new trail in, as Rich is doing. So far, we’ve worked with quail, humans, and now greyhounds; in the past I did some simple studies with horses and elephants, too. Jeff Rankin from my team and other collaborators have also worked on six species of birds, of varying sizes, to see how their squat-stand mechanics change.  Thus we’ve covered a wide diversity of animals, and now we’re learning from that diversity. “Diversity enables discovery,” one of my former PhD mentors Prof. Bob Full always says. Too true.

Greyhounds are interesting because they are medium-sized, long-legged, quadrupedal, quite erect in posture, and very specialized for fast running. Fast runners tend to have big muscles with fairly short fibres. Short fibres are bad for moving the joints through very large ranges of motion. So how does a greyhound stand up? Obviously they can do it, but they might have some interesting strategies for doing so- the demands for large joint motion may require a compromise with the demands for fast running. Or maybe the two demands actually can both be optimized without conflict. We don’t know. But we’re going to find out, and then we’ll see how greyhounds compare with other animals.

To find out, we first have to measure some dogs standing up. We’ve done that for about 8 greyhounds. Here is an example of a cooperative pooch:

Those harmless experiments, if you follow me on Twitter, were live-tweeted under the hashtag #StandSpotStand… I dropped the ball there and didn’t continue the tweeting long after data collection, but we got the point across– it’s fun science addressing useful questions. Anyway, the experiments went well, thanks to cooperative pooches like the one above, and Rich has analyzed most of the data.

Now the next step involves the cadaver of a dog. We could anaesthetize our subjects and do this next procedure to obtain subject-specific anatomy. But it really wouldn’t be ethically justified (and if I were an owner I wouldn’t allow it either!) and so we don’t. A greyhound is a greyhound as far as we’re concerned; they’ll be more like each other than either is like a quail or a human. Individual variation is a whole other subject, and there are published data on this that we can compare with.

We get a dead dog’s leg — we don’t kill them; we get cadavers and re-use them:

Greyhound hindlimb for CT

We study the hindlimb because birds and humans don’t use their forelimbs much to stand up normally, so this makes comparisons simpler. We’re collecting forelimb data, though, as we work with quadrupeds, for a rainy day.

We then CT scan the leg, getting a stack of slices like this– see what you can identify here:

It’s not so clear in these images, but I was impressed to see that the muscles showed up very clearly with this leg. That was doggone cool! Perhaps some combination of formalin preservation, fresh condition, and freezing made the CT images clearer than I am used to. Anyway, this turned out to be a treat for our research, as follows.

We then use commercial software (we like Mimics; others use Amira or other packages) to “segment” (make digital representations in 3D) the CT scan data into 3D anatomy, partitioning the greyscale CT images into coloured individual objects– two views of one part of the thigh are shown below.

What can you identify as different colours here? There are lots of clues in the images (click to embiggen):

Hindlimb segmentation of greyhound

And here is what the whole thigh looks like when you switch to the 3D imaging view:

Quite fetching image, eh?!

The next steps after we finish the limb segmentation are to apply the experimental data we observed for greyhounds of comparable size by importing the model and those data into biomechanics software (SIMM/OpenSim). We’ve done about 40 models like this for various species. I detailed this procedure for an elephant here.

Then, at long last, science will know how a greyhound stands up! Wahoo! Waise the woof! Stay tuned as we hound you with more progress on this research-as-it-happens. Rich just finished the above thigh model this week, and the rest of the leg will be done soon.

Many thanks to Rich Ellis for providing images used here. And thank you for persevering my puns; they will now be cur tailed.

Happy Freezermas! Sing it: “On the fifth day of Freezermas, this blo-og gave to me: one tibiotarsus, two silly Darwins, three muscle layers, four gory hearts, a-and five stages modelling a doggie!” ♪♫

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Posted in Anatomy Vignette, Freezermas, Two-Dog-Night Tetrapods | Tagged anatomy, biomechanics, CT, dissection, freezermas, modelling, reconstruction | 7 Comments

7 Responses

  1. on February 15, 2013 at 4:15 pm franjurga

    That’s great! And here I was, expecting just a lot of dogma…I’m singing!


  2. on February 16, 2013 at 2:22 am Mark Robinson

    I appreciate how you doggedly tried to squeeze in as many canine puns as you could. I think I was able to spot them all. Mastiff been amusing for you.

    Good boy, John. Good boy!


    • on February 16, 2013 at 7:44 am John of the Freezers

      I had a net loss of 3 blog followers for the week so the poochy puns must have been howlingly good!


  3. on February 16, 2013 at 12:09 pm Stella

    I love when you post video models.


  4. on February 16, 2013 at 12:19 pm On the Sixth Day of Freezermas, this blog gave to thee… « What's In John's Freezer?

    […] « On the Fifth Day of Freezermas, this blog gave to thee… […]


  5. on February 17, 2013 at 8:52 am On the Seventh (and Final) Day of Freezermas, this blog gave to thee… « What's In John's Freezer?

    […] and again (gasp, pant)– and again (exhausted howl)… and… aaaaaagaiiiiin… […]


  6. on June 27, 2013 at 10:30 am John of the Freezers

    I see that someone has posted this blog post on their Facebook page and tried to raise a ruckuss with it; based on comments that have been submitted. The comments do not display an understanding of the point of this blog or the post, and veer toward the irrational, so I am not posting them as they do not contribute to the discussion. If you do not like this blog or any of its post, just don’t come here. It is the internet and there is certain to be something that upsets anyone on the internet.

    As I noted above, the dogs were NOT killed for scientific research of any kind. We don’t do that. They are normal mortalities from various sources. We just use the cadavers for research. The research ranges from the fundamental to the applied/clinical, with potential benefits that could help humans, dogs or other species. That’s what is important to take home from this post; the science is sound. I am not a clinician who takes care of your pets, so don’t let my casual nature reflect on how clinical care is done at our college.

    Now, if you disagree with my tone in my post, that’s another issue. If you read point 7 in the “Welcome to My Freezer”/FAQ page (see heading at top), that explains my viewpoint, as does point 2. While the science I do is very serious, I use this blog to lighten up a bit, and I do have a sense of humour that ranges to the dark sometimes, or playful other times. Again, if you don’t like that humour, you don’t have to come here and confront it. When you deal with both the gloomy side of mortality and the beautiful aspects of anatomy on a daily basis, a sense of humour about it all helps.

    I do not feel that having a sense of humour about death or anatomy is unprofessional. It is just my way of processing things, and lightening the mood of what can be a grisly or morbid subject. I do not agree with the view that dead organisms remain sentient or are concerned with the fate of their bodies. When I deal with live animals, I treat them with respect and care; I work at a veterinary college where that is the routine approach and an important one that I agree with. But in my view, a dead dog’s feelings are not hurt by humour, especially long after it has died. You are more than welcome to disagree with that viewpoint; that is what makes life interesting, to have people with different views on the journey of life, and death.

    But irate comments about the way I deal with the situations I encounter are not the kind of “discussion” I wish to feature here. You are more than welcome to feature it on your Facebook pages or elsewhere if you wish to. I hope that you give fair treatment to what this blog/my work is really about. So far none of the new comments here display such an understanding, but I understand that this is part of life, that the way one person approaches a situation may be very different from how another person does.

    I’ve owned dogs and other pets, and loved them dearly, so I can see how some people might not appreciate my sense of humour about cadaveric dogs. But to me a live dog and a long-dead cadaver (especially of an animal that was not the live dog I studied, as in this case and the normal cases I encounter in my work) are vastly different things. So I approach them differently, albeit both with a sense of wonder.

    Edit: I agree that the greyhound racing industry is in trouble, for many reasons. I do not have interactions with them, and this post is not intended to support them. I strongly applaud people who adopt greyhounds as rescue animals from such industries. The welfare problems facing greyhounds and other racing animals are an important issue, and people at the RVC and elsewhere are actively engaged with improving the situation. Change is happening, but I can understand if people feel it has happened too slowly.

    I have shut down comments – I am sorry if the post offended you, but that was not the intent. A majority of the post was about the science; the comments have focused on the off-colour humour. There have been both positive and negative comments but I’ve deleted them all as I don’t see I think they have led to a productive discussion on the emotive issue of greyhound welfare, and that is not the topic of the post. I’ve covered other matters above. I am not entering into a debate here about whether dogs have souls, or if they do whether their souls read this blog or care what I say. This blog is about how wonderful animals are; living and dead; I consider it a celebration of that wonder, which science can help reveal. If you don’t agree, don’t read it.

    Again, the link to the FAQ for this blog:
    https://whatsinjohnsfreezer.com/about/



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