This is the end.I’ve worked hard all week to bring you all-new content for Freezermas, and on the Seventh Day I get drunk rest– and make you do the work! Off into the hoary wilderness you go, seeking answers to eternal trivial mysteries.
Seven mystery photos of museum specimens today, each from a different museum (or other institution whose role it is to display critters, in 2/7 cases) and animal! I’ve visited all these facilities and taken these photos myself. Which specimens can you identify, and (ultra difficult) can you identify the institution it’s from?
Stomach-Churning Rating: 2/10. Super tame.
You had some impromptu practice on day 2. Very well, then. This session counts for points. If you want a recap of points, see last Mystery Dissection.
But because the pictures are small and numerous (refer to them by number 1-7, please), the points/correct answer are simplified: 2 pts for correct answer, and maybe 1 bonus pt for something clever but incorrect, 0 pts here just for shooting the breeze (“Superhuman effort isn’t worth a damn unless it achieves results.”–Ernest Shackleton), plus 1 pt extra credit if you correctly ID the museum/institution. Being first does not matter here. Just being correct. With 7 mysteries, you can freeze up a lot of points here! But…
Difficulty: Cropping. Lots of cropping. And therefore quite pixellated if you zoom in much; don’t even bother clicking to embigitate. However, there may or may not be themes between some pictures, or critical clues. They are identifiable.
Off you venture, brave Freezerinos! Wear multiple layers.
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But wait– there is a mystery eighth specimen, which even I am not completely sure what it is! No points for figuring it out, but mucho respect!
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 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 a maximally cooperative pooch: a dead one. 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, giving them a [sunglasses] new leash on life:
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):
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. Whelp, it was fun while it lasted, but it’s time to pull the pug on it without further paws, so you don’t flea.
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!” ♪♫
Today I’m shimmying down your interwebz with a late delivery. I’ve promised before to show how we clean up our nasty gooey skeletons to preserve them for future research to use. This is the intended final destination of all critters that are tenants of my freezers– the freezer is just a lovely holiday home, but bony heaven is the end result. I’ve accumulated a little museum of the bones of exotic animals I’ve studied, using these cleaned specimens. Here is how I do that preservation– there are four basic steps, and I’ll show them in four photos.
Stomach-Churning Rating: 8/10; first just dry bones, but then some gooey bones and by the end we ratchet it up to bloody organs.
Step 1) We get the deceased animal from various zoos and other EU sources, CT/MRI scan it, and dissect it. That’s what most of this blog focuses on, so I won’t show that. But I will show the end result, and then how I get to that:
Those are some elephant and rhino bones, some of which you saw on the 2nd day of Freezermas. Elephant bones are super greasy; it’s almost impossible to get rid of that brown grease visible in this photo (upper LH side) without making the bones brittle and over-bleached. The bones of the whiter white rhino on the right show what I’m usually aiming for. How do I get this done? Well, here’s an example for an elephant shank:
I take the elephant shank and make soup. (above) An Asian elephant’s patella, tibia and fibula were dissected, frozen for many years (queued up for cleaning; much freezer burn occurred on this specimen— it was jerky-fied), and then thawed. I put large specimens in this Rose cooker unit, which is a big ham cooker with a heater unit at the bottom. My baby, a Rapidaire MKV 5-ham unit is shown; oooh, ahhh!
The Rose cooker is filled up with tap water and been set it at around 60-90C. Then I let it cook away! A brothy soup develops, and sometimes it smells rather nice (my favourite aroma is giraffe leg). Sometimes… it’s not so nice. We check it every few hours to top up the water and remove stray tissue, and then change the water every day or so.
An elephant shank like this will take 2-3 days of cooking, longer if only switched on during work hours. The key thing is not to let it cook dry, which happened once with a faulty Rose cooker that did not do its normal auto-shutoff when the water ran low… showing up to work to encounter some fire trucks and unhappy college Health & Safety rep is not a good way to start your day, trust me!
This step is only slightly different for smaller (<30cm) specimens. Rather than the Rose cooker, we use the lovingly named “Croc Crock”, which isn’t visually impressive but you can see it here. As the name indicates, we’ve mainly used it for small crocodiles, and it is a crock pot. (a helpful thing is to add some detergent to the water for these small specimens; then bleaching isn’t so necessary)
Step 2) Then I empty out the water through the bottom spout, do the very nasty job of cleaning out the fat and other tissue that has accumulated (think 20 gallons of goo), hose off the bone, and set it in a ~10% bleach solution for at least a day, or up to a week or so for an elephant bone. Once it’s cleared up, I leave it out to dry (for big elephant bones, copious amounts of grease may be emerging for a few weeks). And then…
Step 3) I varnish the dry bones with a clear varnish, and let them dry. Here is how that elephant shank turned out. Pretty good! Finally, they get to join their friends:
Step 4) The prepared bones are labelled, given a number/name that I file in a world class comprehensive electronic database (cough, get on that John, cough!), and they become part of my humble mini-museum, shown above. Voila! The chef’s job is finished. Let science be served!
Happy Freezermas! Sing it: “On the fourth day of Freezermas, this blo-og gave to me: one tibiotarsus, two Darwin pictures, three muscle layers, a-a-and four steps of bone cookery!” ♪♫
Oh it’s Valentine’s day, so, err, have a heart today. Have four, actually!
…a daily picture of anatomy! And today it is two pictures, tra-la-lee!
Welcome back to Freezermas! And HAPPY DARWIN DAY! Last year our whole lab got involved in DD2012, but this blog was just a twinkling in my keyboard back then. This year it was a more mellow, somber occasion for DD2013. But Heinrich Mallison of the dinosaurpalaeo blog took part, and took photos (all credits go to him), and the result kicked ass and took names. Bring it on!
Here is Darwin amidst a selection of greatest hits from my bone collection; post-freezer denizens. How many can you identify? Have a go in the comments below. A few should be quite familiar to blog followers… More about these bones later this week. Incidentally, Darwin is standing on a Kistler forceplate. So biomechanics afficionados can geek out about this, too.
And here I am hamming it up again. Give it a rest, John! But ’tis merely a humble offering to The Master. I’m sure he’d appreciate it. Any guesses what it is?
Happy Freezermas! Sing it: “On the second day of Freezermas, this blo-og gave to me: one tibiotarsus, a-and two silly pictures with Chucky D!”
Welcome to Freezermas! In the dead of winter, the WIJF blog jumps down your internet to deliver mind-warming science, and images, and evolution! To celebrate Charles Darwin’s birthday (204th = tomorrow Feb 12, 2013), I’m bringing you one Anatomy Vignette each day this week (we’ll see if I can manage the weekend or not)! Let’s do this!
Stomach-Churning Rating: 2/10; just bones; one picture of them, and then a lot of discussion of muscle anatomy but no pictures of it.
The above image comes from one of my old, somewhat obscure anatomy papers (link to pdf here), from 2003. It’s possibly the first figure I made, entirely by myself, that I’m sort of proud of. It doesn’t totally suck compared with some of my other attempts. I did the stippled line drawing on the left, and on the right is one of my first usages of a digital photo in a paper (digital cameras were finally up to the task around that time; I used my new Nikon Coolpix 900, if memory serves). It was a greatly improved figure over what I’d submitted for this paper originally, which was a rushed, half-baked manuscript for a SICB conference symposium on tendons. I’ll never forget one of the peer reviews of the manuscript, which said something like “the text of this paper is a joy to behold, but the figures are a horror.” They were right, and luckily the images in the paper I submitted changed a lot in revision. (I’m still embarrassed by the incident, though!)
Anyway, the picture is of the lower hind limb of two theropod dinosaurs: (a,c) an adult Tyrannosaurus rex, and (b,d) a wild turkey (Meleagris) from my personal collections of dissected-then-skeletonized animals (this turkey became a biomechanical model in a 2004 paper of mine, too!). In both cases we’re looking at a right hind limb; in (a) and (b) from a caudal/posterior/rear view, and in (c) and (d) from a lateral/side-on/profile view.
If you’re having trouble visualizing these bones in the real animal, check this T. rex skeleton in rear and side views and try to find these bones. You can do it! You might also want to look back at my paroxysmic outburst of love for knee joint anatomy.
The thicker long bone is the tibia (your main shank bone; or in a lamb shank, chicken drumstick, etc); the thinner outer bone is the fibula. Together with some smaller bones, for brevity we can call them the tibiotarsus – but only in theropod dinosaurs, or you will anger the freezer gods.
The labels show some cool anatomical features, as follows:
“CC” the cranial cnemial crest of the tibia (a projection of bone unique to the knees of birds);
“CF” the crista fibularis; or fibular crest; of the tibia (more about this below);
“FT” the fibular tubercle (insertion of the big hamstring/biceps muscle M. iliofibularis);
“LC” the lateral cnemial crest of the tibia (a big arching swath of bone that both birds and non-avian theropods like Tyrannosaurus have; the CC is just pasted on top of this in birds); and
“MF” which denotes a muscle fossa (depression) on the inner surface of the upper end of the fibula, which presumably housed a muscle (M. popliteus) binding the fibula to the tibia in earlier dinosaurs, but is vestigial in birds.
The CF, or fibular crest, is a feature that only theropod dinosaurs, among reptiles, develop like this. It evolved early in their history and thus was passed on to birds with other ancient features like hollow bones and bipedalism. It binds the fibula closely appressed to the tibia, making those bones act more like a single functional unit –and sometimes they even fuse together. The CF also transmits forces from the whopping big M. iliofibularis muscle’s insertion (the FT label) across the puny fibula onto the robust tibia. The MF once held a muscle that also helped keep those two bones together, but additionally it could have contracted to move them relative to each other a little bit, as in other living animals (many mammals and reptiles have a big M. popliteus and/or M. interosse[o]us). So these features all have a common functional, anatomical and evolutionary (and developmental; different story for evo-devo fans) relationship. By binding the fibula and tibia together, these structures helped early bipeds (the first theropods and kin) support themselves on one leg at a time during standing and moving, and also helped begin to reduce the limbs to lighten them for easier, faster swinging. So we can think of these features as specializations that helped theropod dinosaurs, and ultimately birds, get established as bipedal animals.
The CC and LC have a similar story to tell; for one, they are muscle attachments, again mainly for thigh muscles. And again, the LC dates back to early theropods (and some other dinosaurs had a version of it; usually smaller). These crests serve mainly as insertions for the “quadriceps” (in human/mammal terms) or triceps (in reptile/bird terms) muscle group’s major tendon, spanning from the pelvis/femur across the thigh and knee to this region. In birds, we call this structure of insertion the patellar tendon or (less appropriately) ligament. But dinosaurs had no patella, ever, so the triceps femoris tendon would be the proper technical term. Regardless, that crest (LC, and later LC too) helped the attached muscles to straighten the knee joint or support body weight during standing/moving, by giving them better leverage. So it would have been important for early bipeds, too, like the CF, MF and other features above. Your cnemial crest (tibial tuberosity) is pathetic by comparison. Don’t even look at it. Droop your knees in primate shame!
Bumps and squiggles on bones might seem puny details just for anatomists to study and describe in long, tedious monographs, but each is part of the great story of evolution, and each has a story to tell that fits into that story. Back in Darwin’s day, some of the world’s greatest scientists of the age (Richard Owen and Thomas Huxley being but two spectacular examples) pored over these seemingly innocuous features, and so they became part of nascent evolutionary theory even then. This week, I’ll be celebrating a lot of those details, which I still feel are important today, and the stories they help to tell.
Happy Freezermas! Sing it: “On the first day of Freezermas, this blo-og gave to me: a tibiotarsus with a CF and FT!”
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