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Archive for the ‘Frozen Mammals’ Category

I have a lot to be thankful for as a scientist, including a great, steady set of blog readers interested in my freezer and its sundry tenants. And now and then I get a fun surprise, like Redditors stumbling across my posts and ramping up my blog views by a factor of 10-20 fold. So this weekend I did (and am still doing at this moment) an “Ask Me Anything” (AMA) on Reddit, by suggestion, and I just crossed 1000 Twitter followers. So I figure I should give some thanks.

And I will give those thanks in a way that I can only do on this blog. With kickass pictures of incredible animal anatomy! Much as I started this blog with giraffes, I will return to them now. And I will let the pictures, with brief captions, tell the tale. These photos are from a dissection our team did quite a few years ago, on an adult giraffe that died suddenly in a local zoo. I forget who snapped these photos– my thanks to them anyway, as I didn’t take them but it was someone from our team.

Stomach-Churning Rating: a 7/10 or even 8/10, depending on your fortitude. Blood, a freshly dead animal, guts, brains, and more.  So before we go further, while you brace yourself if need be, a pic to liven things up. Here I am with my cat (taken a few years ago, too), wishing you Happy Holidays — and much fortitude.

Away we go!

TOSHIBA Exif JPEG

Left side of the neck. Purplish-blue vessel is the jugular vein, shown next.

Left side of the neck. Purplish-blue vessel toward the bottom/eft is the jugular vein, shown next. Nuchal ligament, shown further below, is toward the top.

The jugular vein, opened to show the valves, which prevent blood from flowing back down the neck.

The jugular vein, opened to show the valves (little pockets), which prevent blood from flowing back down the neck.

Cross-section of trachea (windpipe). A narrow tube should give less dead space to move in/out with each breath, so it makes sense for such a huge, long-necked animal to have such a thin trachea.

Cross-section of trachea (windpipe). A narrow tube should give less dead space to move in/out with each breath, so it makes sense for such a huge, long-necked animal to have such a thin trachea.

The nuchal ligament, which runs along the spine and helps hold up that long neck.

The nuchal ligament, which runs along the spine and helps hold up that long neck.

The big heart, needed to pump blood up that long neck to the head.

The big heart, needed to pump blood up that long neck to the head. Compare with the elephant and rhino hearts posted here before.

Left shoulder and ribcage, muscles peeled back.

Left shoulder and ribcage, muscles of the triceps peeled back. Shoulder blade (scapula) visible. The neck extends up to the left corner.

Left side of chest, rumen showing through behind ribcage.

Left side of chest, rumen (fermenting tank) showing through behind ribcage. Forelimb has been entirely removed here.

The left cheek's teeth-- and check out the spines on the inside of the cheek! Keratinous growths to aid in chewing, food movement, digestion etc. These extend into the stomach, too! Amazed me first time I saw them, in an okapi (giraffe cousin).

The left cheek’s teeth (molars)– and check out the spines on the inside of the cheek! They are keratinous growths to aid in chewing, food movement, digestion, protection against thorns, etc. These extend into the stomach, too! These amazed me the first time I saw them, in an okapi (giraffe cousin).

The brain.

The brain, in bottom view. Olfactory nerves leading to the nostrils near the top (whitish), and optic chiasm for the eyes (“X” shape behind the olfactory nerves) are visible, then the medulla oblongata, smallish cerebellum and the spinal cord. For a human brain diagrammed and labelled in similar view, see here.

Like rhinos, elephants and many other large mammals, giraffes (especially in captivity) are vulnerable to foot/hoof pathologies, such as this very skewed/divergent pair of nails. This can lead to them walking very abnormally, getting infections or arthritis and other problems, so it is very serious.

Like rhinos, elephants and many other large mammals, giraffes (especially in captivity) are vulnerable to foot/hoof pathologies, such as this very skewed/divergent pair of nails on the right front foot. This can lead to them walking very abnormally, getting infections or arthritis and other problems, so it is very serious.

The tapetum; reflective coating of the eye that can aid in night vision and protect the eye a bit. Gorgeous!
The tapetum lucidum; reflective coating of the eye that can aid in night vision and protect the eye a bit. Gorgeous!

Hope to see you again here soon!

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Well, I’ve been pretty busy with grant-writing and other stuff lately, so I’ve been neglecting my beloved blog. Here is a little sequel to my Animal Inside Out exhibit review, from my 2nd visit there, yesterday. I had previously missed the “3-headed camel” that is in one corner of the great hall (the Diplodocus one overlooked by Darwin). Because that is outside the special exhibit, there are no issues with taking photos, although I must apologize that as usual I just had my mobile phone’s camera. So here you go– a camel anatomy extravaganza. Too bad I didn’t do this on Hump Day

(beefy reward at end for those who view all the pics)

Front view.

Side view.

Back right view. Naughty boy trying to grab the guts. It’s not a petting zoo, kid!

Back view. Kid nearly has snatched some precious entrails.

Front right view.

Cranial view of forelimb. Now I’m starting to get pretty interested in documenting the muscle anatomy for my own records. These AIO displays really do clearly show the myology.

Nice view of right triceps, latisssimus, carpal extensors/flexors, etc.

Guts, glorious guts! Beautifully sectioned stomach, showing “pseudoruminant” three-chambered structure and smaller compartments within.

Right hindlimb, rear/side view. Great view of semimembranosus/tendinosus, biceps femoris, superficial gluteal, tensor fasciae latae?

Left distal hindlimb, side view, emphasizing (toward bottom right) calcaneal “Achilles” tendon, and possibly a slip of the very reduced plantaris muscle? Also distal tendon of hamstrings prominently visible, with belly toward top of image (dark).

Left forelimb, showing elbow region with triceps/anconeus, more carpal flexors/extensors.

Great exhibit. No bullshit.

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Like I said, oh hai! Wow, I wasn’t expecting all of you here! Enjoy a random photo of some awesome anatomy, Boing Boing universe, and thanks for the nice story!!

Note that an elephant’s heart does not end in the stereotypical single apex (point) at the left ventricle. Elephants have a 2-pointed heart, with two large ventricles used to pump blood to the body AND lungs… who else has this feature? Ahh yes, their closest living relatives: seacows (manatees, dungongs; the Sirenia)! Probably a leftover swimming adaptation. Big, muscular ventricles (the darker purplish tissue to the left and right of the yellow-pinkish line of tissue running from top to bottom along the middle) are useful for pumping blood against resistance, such as when using the trunk as a snorkel while swimming.

The bottom of the heart is at the bottom of the screen; you’re looking straight at the front of the heart.

Human heart for comparison, from Wikipedia; scale relative to pic above is not too far off (elephant relatively a bit undersized):

For more info on elephant hearts, see here and here, and for the hardcore anatomists, here and here.

And more about elephants from Inside Nature’s Giants, too!

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There’s no better way to kick things off after a holiday than with a celebration of the Inside Nature’s Giants series, which I had a small part in early on, including these shots I took during the time they spent filming at the RVC >3 years ago (!?!?); most of these animals spent multiple holidays inside The Freezers:

Elephant arriving…

Elephant revealed

Private moment with elephant

Stunning emergence of The Guts

So you are impressed by the guts too, ehh? It was pretty amazing to watch it happen. The tension was intense- the animal had been dead for a while and was rather bloated. So cutting it open was a task gingerly taken…

Bloated elephant

RVC dissector Richard Prior stuck a scalpel in the upper abdomen when the time was right… the piercing whistle and the sulphuric odour silenced the crowd watching… and then quickly out came the guts.

Everyone was pretty amazed by the scale.

The guts just went on and on…

Not a 1-person job by any means.

Spreading them out to see the whole GI tract.

I waited patiently and watched the show filming; what a great, professional crew. Then I got to take the legs away for our research.

But not just elephants, no sirree! The Windfall Films/ING team filmed giraffe, crocodile and big cats episodes (4 total) at the RVC too; a crazy period of a few weeks (including a major blizzard that hit us during the croc filming) in 2009. Some of the stars follow:

Frozen lion waiting for CT scan, shot 1

Frozen lion waiting for CT scan, leg shot

Frozen lion waiting for CT scan, shot 2; eerily contorted pose

Frozen tiger waiting for CT scan, shot 1

Frozen tiger waiting for CT scan, shot 2

Frozen tiger waiting for CT scan, shot 3

…and here is the tiger’s head after scanning

…and I’m rather fond of that tiger’s neck– check out the hyoids (roaring/tongue apparatus in throat; bottom of movie)!

…and here is the adult Nile crocodile’s head after scanning

…and another view of that big Nile croc, just because I like how this reconstruction turned out

…and here’s one of the small (~1m long, 10kg) juvenile Nile crocodiles from the show, with a pilot CT scan showing the skeleton nicely- and possibly a last meal or stomach stone on the left side of the abdomen (bright white blob; I need to check this now that we’ve dissected it)

Foetal giraffe; stillborn; from the show, in process of dissection in our lab to measure its limb anatomy. Trust me, it looked –and smelled– better on the inside than it did from the outside. Eew.

How most of the specimens from the first 4 episodes ended up after all dissection was done (part of my/RVC’s collection of skeletons). Sadly, I did not get great photos of the 3.7m Nile crocodile or the two giraffes before they were reduced to bits, but I do have the skeletons and CT scans.

Giving a tour (including The Freezers) to A Certain Esteemed Visitor.

(Another) Gratuitous shot with one of the sweet old Red Kangaroos at Alma Park Zoo near Brisbane, Australia. Experiments on hopping we did there will be briefly featured in the new Inside Nature’s Giants show on Channel 4, 16 April @2000- details at http://t.co/SkjsMeVC.

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Heinrich Mallison’s photo-rific dinosaurpalaeo blog has the first of what might, if the Gods of the Freezers remain kind, be a series of posts on our dissections of some of the verrrrrry same giraffe limbs featured earlier on this blog. Have a brush with greatness- see the giraffe legs in deconstruction! For free! What more fun could you possibly have (legally)?

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Here now is the promised blog post, which uses the rhino foot mystery pic as a springboard to address a phenomenon that is a bit better known, partly because it is an even worse situation and involving (arguably) even more charismatic critters: elephants.

A rotating movie of a CT scan reconstruction is a good way to kick this off:

This shows the right hind foot of an Asian elephant that had mild pathology; mostly a roughening of some of the bone surfaces that is called osteitis (proliferative bone growth possibly due to infection or other irritation) and perhaps a mild case of degenerative joint disease such as osteoarthritis. But this is nothing compared to the severe cases we’ve observed in other elephant feet, and indeed may not have anything to do with why this elephant died (I’m not sure; I was given very little medical history for this one).

If you want more elephant anatomy lessons, see the videos from the posting on six-toed elephants. I will proceed assuming some basic familiarity with bones of the feet in animals, although you may be just fine even without that.

About 50% of elephants in captivity die from foot disorders of one kind or another. Elephant keepers spend a huge amount of time and energy taking the best care of elephant feet that they can, but a variety of factors including anatomy, biomechanics, exercise, obesity, ground surface, hygiene, “hoof” care including trimming, nutrition, and much more are part of the very complex causal nexus underlying these disorders. Wild elephants get similar problems, too, but less frequently (e.g. in drought periods, I’m told); there are few solid data on this, however.

Onwards, then! I shall present a cavalcade of horrific examples of the kinds of elephant foot pathology that we have observed in specimens that have come through my freezers at the RVC.

Let’s start with what one of our vets might see on examination of a live elephant at a zoo:

This is an x-ray image of the third (on the left) and fourth (on the right) toes of an elephant’s front foot. The RVC (Dr. Renate Weller and myself) have developed protocols to take such x-rays on live elephants.  The anatomy shown here is pretty normal and non-pathological. So with that in mind, check this out; toes four (on the left) and five (on the right), different animal:

Ouch! Digit 4 (“ring finger”) has a proliferation of bone that is characteristic of an animal with osteomyelitis: a flowering of bone in response to infection and painful swelling, probably caused by an abscess on the toe’s sole/nail. This animal was put down because of its unresolvable misery from this disorder. Oddly, we see toe 4 as well as 3 and 5 as the most commonly pathological; toes 1 and 2 seldom are. We’ll be discussing this in a new paper coming out soon; I’ll get back to that another day.

Assuming such conditions don’t resolve, the next place the foot may end up is in The Freezer at the RVC, and then into our CT scanner before we do postmortem dissections and a report on the pathologies so the zoo knows what went wrong. Here’s an example of what we cut off the end of the fourth toe of such an animal:

Just looks like a glob of tissue, right? The joint between two segments of the toe is visible as a pinkish white structure on the right side, with some bleeding on the cartilage where it wore down to the bone surface. But it gets worse. Here is how that same toe bone looked when we cleaned it up (boiling and bleaching away soft tissues):

Here, that same roughened joint surface is visible at the top of the specimen. Two toe bones have become fused together (the bottom one is not visible), encased in a cocoon of lacy, spiny bone. Again, ouch. The next specimen had a different kind of “ouch”- its fifth toe basically shattered:

That toe is almost unrecognizable, having disintegrated rather than proliferated its bony scaffolding. Other specimens may be in less extreme states of pathology but still likely to have been in pain:

The label here says it all; third toe with a cyst where an infection entered the bone.

This one, the end of a third metatarsal, shows degenerative joint disease with a loss of articular cartilage, and holes where abrasion has worn down into the bone and caused bleeding. In contrast, and to give you a breather from the horrors, here is a healthy, younger elephant’s similar joint surface:

Nice white, fresh, shiny cartilage! Ahhh…

But then we dive back into Grand Guignol-level aberrations:

Here we’re looking at the back side of a right hind foot of an elephant, at the level of the ankle joint. The joint capsule surrounding the ankle joint has been cut open in my dissection to expose the terribly pathological, but still somewhat white and shiny, cartilages (middle of the image) which have been abraded (in some regions) but also extended by new bone formation (in other regions) to creep around the back of the ankle. Here, the bone growth was fulfulling a role to limit joint mobility and thereby restrict painful joint motions- the joint was fusing into an ankylosis (no, not an ankylosaur,  but same Greek root). Here is a closer look, removing the tibia and fibula that were at the top of the screen in the above image, and looking down onto the ankle joint surface:

You should be able to more clearly see how the cartilage and underlying bone are not forming a smooth edge, as they should on the talus (ankle bone), but rather an irregular, jagged contour (area to the right of the label). This animal would have been visibly lame, to say the least; elephant ankles can’t move much even in normal animals but this one was even less mobile. We’ve had some specimens where the ankle was so fused it was totally immobile and took a saw to separate the two sides of the joint. Oddly, I haven’t seen an ankylosis like that in the wrist, which in normal elephants is as flexible a joint as the ankle is inflexible.

Pathologies like these sadly aren’t uncommon in elephant feet but zoo/park keepers are doing their best to turn the trend around. Zoo conditions generally were a lot worse 50 years ago. The pictures below document this, from museum specimens we’ve studied (among many others) at the University Museum of Zoology at Cambridge and the Natural History Museum in London. See what pathologies you can spot! Some are from wild-shot animals, reinforcing that foot pathologies are not just a zoo thing. (click to embiggen)

      

Zoo/park conditions are improving now— in the UK for example, elephants are being moved into more safari park-like environs and given more varied surfaces to walk on or even dig (e.g. sand at Chester Zoo). But because elephants live long lives, and foot pathologies sometimes cannot be reversible (or even detectable, sometimes), any pathologies existing now may well still be evident, or even worsen despite the best care, for decades to come. The lag time for fixing the global problem of elephant foot pathologies is not a short one. I won’t get into the controversy over whether elephants should be in zoos/parks or not, but at least for the short to medium term they are, and we need to make the best of that. The images in this post help show why, and perhaps point a way toward how.

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In case you missed the story about this paper released just before Xmas, here are some links to stories about “From flat foot to fat foot: Structure, ontogeny, function and evolution of elephant “sixth toes,” in Science, 2011:

1. The paper (free download from my publications list; nice policy, Science!)

2. Our website about the paper (more imagery goodness!)

3. Ed Yong’s first (Nature News) and second (more detailed blog) article

4. BBC News’s story

5. Reuters TV‘s excellent video

6. Science Now/Wired’s story

7. Daily Mail‘s story (not a daily fail, in this case)

Clarification: it’s not a real sixth toe in elephants; it’s a false, toe-like structure (“predigit”) made from other tissue. That confusion seeped into some media stories. But this whole story ties into the thorny question of what a digit (finger/toe) is and how we can tell (e.g., notions of homology). Regardless, the elephant predigits are present in all four feet, and are super duper cool!

Most importantly for this blog, that research relied, and still relies, on our fabulous freezers to keep the elephant “toes” in snuggly cold conditions until we wanted to study them.

The research is continuing- I’ll post more about that later. We’ve been doing lots more histology to explore the complex ways that these predigits are formed, and also studying how they function (ex vivo) in more 3D detail than before (with new comparisons to rhino feet). Also, a new paper of ours will come out in J Experimental Biology very soon. It elaborates on how whole elephant feet function, across ontogeny, using in vivo pressure patterns.

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William Pérez from the Veterinary Anatomy Facebook page sent me a link to this stunning image of a giraffe hindlimb dissection– wowza!

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Scanner's eye view of giraffe leg

This is why we get scan artifacts from giant specimens. It fits, but only just. The x-ray beams are getting scattered from being too close to the x-ray detectors (ring around the specimen), creating noise in the images. The red lines on the specimen are from a laser, used to align it properly within the gantry of the scanner. The femoral head (hip joint) is visible as the pale white thingy, down on the bottom right.

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We use Mimics software, which is pricey but sooooo easy to do stuff like this. Here I’ve just had a very quick pass at reconstructing the distal hindlimb (limb except the thigh, which had bad scan artifacts). With more effort, I could remove the pesky artifacts around the knee and ankle (2 uppermost joints), although some of those are unavoidable because the leg was too damn big for the CT scanner gantry (70cm diameter; leg was around 60cm across at largest).

So how long did this process take? The hardest part was moving the leg around and positioning it on the CT table. Then the scan (608 cross-sectional slices) took about 15 minutes to do, then 15 more minutes to transfer over to my PC. Loading the DICOM slices of data and making a movie (previous post) took 5 minutes, and then making this 3D reconstruction movie took just another 5 minutes, although I waited a few days because I was busy.

So, when operating at peak efficiency, we can obtain decent 3D models from frozen specimens in less than an hour. This is but one example of how modern technology, especially X-ray computed tomography and computer hardware/graphics software, have massively transformed any research that deals with anatomy. When I was doing my PhD back in the 90’s, this would have been a much more time-intensive procedure (probably weeks of work, and difficulties getting CT access); in the 80’s it would basically have been impossible.

In the future, now, we’ll be using these models (once cleaned up a bit) with data from dissection to model how the limbs work in a real giraffe. More about that later. The Giraffe-A-Thon is over for now. I hope you enjoyed it! More of the same to come on this blog!

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