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Posts Tagged ‘elephants’

RVC’s Lovely Little Anatomy Museum, Part 1

Posted in Museums are Cool, tagged , , , , , , on June 30, 2012| 5 Comments »

Welcome to the first of a series of image galleries with highlights from the RVC‘s Anatomy Museum! Our veterinary school dates back to the 1789 epic dissection of the unbeaten racehorse Eclipse by surgeon Mr Charles Vial de Saint Bels, which led to the college’s founding in 1791 (incidentally, the RVC retains Eclipse’s skeleton to this day, and 80% of living racehorses come from Eclipse’s lineage!).

What, you didn’t know we have an anatomy museum? Well this is another of London’s many hidden museum treasures. It is based at our Camden campus, just a 10min jaunt from King’s Cross or St Pancras stations (or Mornington Crescent tube), in the colourful Camden Town neighborhood. It doesn’t have its own website, yet, and my posts are not intended to play that role, but I want to informally and unofficially celebrate its glory because I think we have a great museum full of wonderful features and people deserve to see them.

For example, when I first interviewed for (what became) my job at the RVC in 2003, one of the first sights at the Camden campus was the original, classic ~Victorian style (dark and gloomy, stained wooden cabinets, room chock full of skeletons) anatomy museum which presented the entrant with a lovely view of this:

Which sadly is my only photo of the skeleton of an Asian elephant that shows it in its original position, crowded next to the skeletons of a white rhino, common hippo, horse and other animals. If you know me and my penchant for giant critters, that was like being shown the Promised Land! Since then, modernity has required us to clear out the dusty Victorian room and rehouse the specimens in more airy, spacious surroundings. Which has worked out pretty well in our case, I think. Here is the elephant now, in the midst of our cafe next to our Anatomy Museum (sadly, the rhino and hippo are mostly now tucked away in storage, and no, there is no rhino horn here for people to steal. Sheesh!):

Much easier to walk around, drink coffee with, etc., and it has gained a second skull (with the skull of a baby also on display nearby). So you might immediately be able to see why I like our museum– any museum with a mounted elephant skeleton rocks, in my opinion. But also, I’m gradually cleaning up my freezer specimens, building a little museum of “my” own that will eventually become an official part of the RVC museum’s collection, so there is a connection to this blog too.

Anyway, here is what a visitor gets as a first impression upon entering our museum:

Namely, a horse who is less famous than Eclipse but still no slouch in his day, Foxhunter the show jumping horse, who won Britain its only gold medal at the Olympics 70 years ago (nice timing)! Then, looking around the museum, you will see:

A cow skeleton to your left, which is no shock at a vet school, but then look more closely, to the right:

A nice tiger skeleton is mounted there, with a pig skeleton atop it, and a hippo skull hanging out nearby (closer view of that in a later post). Through the green doors to the right is our lovely cafe, with the elephant and a few more specimens including a splendid mount of a sitting polar bear (to be shown later). And then, meandering around back to the left through the museum hall you will find:

A nice replica chimp skeleton next to a cast of “Lucy”, the famed Australopithecus early hominin! So there’s some decent evolutionary context in the exhibit, too; not just your standard domestic critters with little broader conceptual unification. But I think some of the museum’s greatest treasures  are the preserved specimens of lovingly dissected animal anatomy demonstrations, such as toward the back of the room:

These were done over past decades, many winning awards for the skill displayed in making them, and it is sad that this skill is becoming more and more rare, with shifts toward less hands-on, more computerized education and training. At least BodyWorlds and Animal Inside Out bucks this trend! It’s fortunate we have museums to show off the skill of preparators and dissectors so the beauty of such specimens can continue to be appreciated. I’ll show some closeups later.

There are plenty of surprises in the RVC’s Anatomy Museum, so if you get a chance and expect to be near our Camden Campus, come take a look sometime. Casual, unheralded visitors are not normally welcome, as the museum is more of an in-house educational resource than a public one. But I am told that scientists could easily get entry to study specimens on prior request, and with plenty of advance notice other members of the general public probably could, too. Mr Andrew Crook (recently awarded an MBE for his efforts using our museum and other facilities to educate local students) is the main contact person but please don’t swamp him with requests. It would be best to contact me first for advice and contact details.

So there’s a little introduction to our Anatomy Museum, and coming posts will show you more of the cool specimens within– stay tuned!

I’ll have our friend the ostrich skull show you the way out–

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An Anatomist’s View Inside “Animal Inside Out” (a review of the NHM exhibit)

Posted in Geeking Out, Reviews, tagged , , , , , , , on May 24, 2012| 34 Comments »

Title is so meta?

OK Londoners, and Olympics visitors, and anatomy (or just science/biology) buffs, and those not lucky enough to see other versions of the animal Body Worlds show. You have a mission. And that mission is to go see “Animal Inside Out”, a special (£9 for adults is well worth it!) exhbit at the Natural History Museum, open until September 16. This blog will self destruct, very messily, by turning itself inside out in 5 seconds… Boom.

Hippopotamus attempting to outdo elephant guts.

Anatomy to me is beautiful even when it’s “ugly” (messy, wet, mucosal, intestinal, asymmetrical, unlike human, whatever), and that’s a major theme of this blog. Hence I am embarrassed that I hadn’t yet gone to see this Body Worlds spinoff exhibit until now, but can begin to shake off that shame by means of an almost exclusively effusive gushing of blood love for said exhibit. Wow, wow, wow! I went in with no particular expectations, having seen some pictures and knowing some of what to expect, and having other things on my mind. I came out very pleased; the NHM exhibits folks and von Hagens’s crew have created an inspirational spectacle that could do wonders for anatomical sciences and natural history. More about that at the end.

(Warning: possibility of spoilers, but the exhibit is so visual that I don’t think my descriptions can spoil it)

The entrance

No photos are allowed as usual, so all I have to show you is the entrance and some anatomy pics I’ve interspersed from my team’s research to lighten up the text. I suppose I could have asked for special permission to take photos for review usage but this was a very impromptu visit, and with ~4 months of showing left I may well be back again.

Weighing a hippo; spot on at 1600 kg!

There is a brief panel on homology and why it is the major concept underlying comparative anatomy (and a key part of evolution, co-opted from the not-so-evolutionary ideas of Sir Richard Owen, whom the NHM rightly mentions here). Another panel rightly brings up the issue of ethics, which has plagued Body Worlds before. It comforts the visitors that animals were not slaughtered just for this display and that the NHM applied its strict collections criteria to them. Convincing enough for me, and absolutely necessary to bring up early on.

The entry hall then presents you with about five cephalopods (labelled “squid” and “octopus”—a gripe is that species names/details are not given for most specimens on show) prominently occupying the view. The cephalopods, like basically everything else, are plastinated (by a now US-patented set of procedures, I learned from the exhibit book detailed later). They are stunningly frozen in lifelike poses or with gaping cuts to show their interior anatomy, although there was very little explanation here about cephalopod biology and anatomy (about 1 smallish panel). No mention of Cthulhu. Damn. He’d approve of the Grand Guignol scenery.

Toward the back of the first corridor of specimens and cases, there is a stunning scarlet haze outlining the body of a “shark” (species not given) with its huge liver lying below it. The haze, a technique used repeatedly throughout the exhibit, is some kind of corrosion cast of the circulatory system, I gather. A bunch of cross/longitudinal sections of cephalopods, crocodiles, fish, horse hooves and other animals decorate blank spaces on the walls, some with labels showing basic features and some just hung like paintings. Fair enough, but a missed opportunity for a bit more educational content here.

Gratuitious Melanosuchus (black caiman) shot.

A smallish whole shark confronts you as you turn the corner from the crimson chondrichthyan; again of unknown classification. One would think a museum exhibit would care about classification beyond “shark,” but oh well, I am banging the same drum here too much and missing the point, that the exhibit is really a visual, visceral expose rather than a deep prose-driven intellectual dissection. On one of the shark panels it is noted that sharks have red and white kinds of muscle used for slower and faster swimming, but not clarified that this is a very widespread vertebrate (chordate?) feature. This forms my second gripe, that a truly evolutionary approach, such as that taken by dozens of the museum’s research staff as their major paradigm of phylogenetic systematics, could have helped the public grasp the evolutionary, hierarchical nature of homology and depart with accurate information about what features characterize groups at which levels. I’m not asking for cladograms laid out on the floor as at the American Museum of Natural History, although maybe that could work, but the exhibit tended to fall back on an outmoded “this animal has this feature, and that animal has that feature, and these are cool adaptations” shopping list approach rather than a modern comparative approach. Granted, almost all museum exhibits fall into this trap, for various reasons and some of them justified. But with a spare word or phrase here or there, this could have been done better without drowning the visitors in that dreaded sea of bloodprose.

Passing the sharks, we come to one of several thematic sections about body systems, this first one on the skeleton (later, brain/nerves, circulation, muscles, etc.). A few small skeletal specimens of the type that are seen throughout the museum are presented, with a scallop reminding us that skeletons can come in many types among multicellular organisms. There is a horse skull and a stark white whole skeleton of a young-ish ostrich, which was very nicely mounted. However, I was caught off guard by the pelvis, which lacked the curved, ventral “boot” like connection of the pubic bones that ostriches have—presumably explained by its juvenile status although I wasn’t 100% sure it was even an ostrich pelvis. OK, I am having a serious pelvis-nerd moment here; forgive me as my PhD was on this stuff.

Ostrich in the midst of disassembling.

BUT, once again the small interpretive panel had a moment of Fail. The ostrich was explained to have two toes, in contrast to normal birds which have “five”.  HUH? Birds have three main toes and variably also a fourth, inner (first) toe called the hallux, used for perching and other activities including walking. None have a fifth toe; indeed their dinosaurian forebears lost that feature some 230ish million years ago. Just an embryonic vestige of the base of the fifth toe is visible in bird embryos today. Furthermore, the panel said that two toes in ostriches can grip the ground more strongly than more toes in other birds. I know of no evidence that shows this, and suspect that the contrary might be true. The standard explanation for toe reduction in ostriches is that it is a lightening feature characteristic of “cursorial” (long-legged, sometimes fleet/efficient) animals, to make swinging the long legs easier. These errors really should have been caught by involving experts in polishing the scientific content of the exhibit.

But I don’t want this post to grumble too much; wrong message. There was so much to celebrate in this exhibit, which was felt impressively spacious and full of cool specimens! Visitors pass some plastinated whole sheep and goats, with panels nicely explaining that goats and sheep look quite similar on the inside and are evolutionary relatives. Having “four stomachs” (technically, a four-chambered stomach; not four distinct organs that were duplicated) is attributed as a sheep trait, then being a ruminant is said to be a goat trait; this might get a little confusing for non—anatomists (both are ruminants and have similar stomachs).

I learned that goats have an extra tail muscle that allows them to swing up/down as well as side-to-side. Hey, I teach veterinary anatomy and I don’t know that!? I must tuck my tail between my legs in shame, but I am no goat so I do not think I can (do satyrs count?). But I wasn’t so sure that goats, as described, were the first animals to be domesticated—I thought that was dogs? Ahh, Wikipedia says dogs, then sheep, then pigs, then goats? I’m outside my expertise here, I admit, and resorting to Wikipedia out of ignorant desperation. Anyway, here, another instance of coulda-been-more-phylogenetically-specific presented itself: the forelimb of goats was said to be connected to the thorax by muscles and ligaments, not a joint, but this is a feature common to most Mammalia. Although audience attentions might be wandering at this point, waiting for the next big spectacle (goats and sheep are not a big crowd draw, even plastinated), some more care as to what was written would be good. Some reindeer and horses and other animals join in the fun later on. Good, but mostly ‘filler’ (wise to put these in the middle of the exhibit, after sharks/cephalopods and before climax) unless you’re a big fan of fairly familiar ungulates with fairly homogeneous postcrania. OK, my bias is showing…

Gratuitious image of emu curled up for CT scan.

Next along the path, a longitudinal section of a whole ostrich caught my attention. Wow again! I had no idea that one could make a section like this of such a large animal, all in one plastic sheet like a giant microscope slide! I stared at this for a while, wondering how both legs could be fit in a ~1cm thick panel, and gave up trying to understand the technology. Von Hagens, you got me there; I’m stumped. Were multiple sections glued together somehow to produce a pseudo-2D slice from many thin 3D sections? I could not tell, and felt humbled and deeply impressed by the technical skill shown in the exhibits so far…

And then the punches kept coming, one-two-three! The exhibit approaches its climax with a crescendo of great specimens in the final hall. First, another maroon marvel. A whole ostrich, standing with wings askew, showing off its entire circulatory system (plus a few wing plumes for aesthetics) from head to toes! Gorgeous, technically brilliant, and well worth at least a 5 minute walk around (you can stroll around many of the displays in 360 degrees- very good move!). A plastinated whole ostrich stands next to it, and for a muscular anatomy geek like me, it was nirvana. However, in a churlish moment I had to look away from a panel explaining that an ostrich is “too heavy to fly” (I admit some younger visitors may need reminding of this). But then I looked into the big open space of this main hall, and the climax was before me. I think I’d had my climax a few times since this, but wow this was enormous in so many ways. All the ways. Mind-blowingly, vastly, geektastically kewl.

Gratuitious rhinoceros leg.

Across from the two posed ostriches and flanked by numerous smaller specimens, the elephant and giraffe stand frozen in vigil. There is also a lovingly detailed dissection of a huge male gorilla by the back wall and exit, with a panel reminding us that gorillas are (among) “our closest relatives.” The giraffe is precariously poised on one front toe-tip, in mid-gallop. What a great pose! There is the requisite explanation of how they solve the blood pressure problem in their neck (e.g. arterial valves), but also the statement, news to me, that they are the only animals able to ruminate while running. Who figured that out and how? I really want to know! Must be hard to check. (or was walking intended? Are my notes wrong?) Across from the full-fleshed plastinated giraffe (which I could see with my eyes closed after all our dissections from a month ago), there was another visually arresting and technically monumental giraffe on exhibit: one represented completely by small, reddish cross-sectional slices, from head to toes in a standing pose. That took me a while to absorb, it was so lovely, almost like a hanging mobile of morphological splendour.

There is a panel about genes and variation and inheritance. It is brief. (and it belongs there) Thank you. Let’s celebrate anatomy for anatomy’s sake for once!

“But John,” you might say, “What about the elephant? No love for the elephant? The star of the show?”

Zoinks! I want one! Stoic and triumphant (except against death and plastination), the Asian elephant is the centrepiece of the collection. (The book explains it was “Samba” from Neunkirchen Zoo, Germany, dead of some circulatory problem in 2005 and the first one plastinated, plus the inspiration for the animal show). I was speechless and paralyzed for a moment. I didn’t even know how to start looking at the partly-exploded-to-show-its-insides elephant. I actually avoided it for a while, looking closely at the other specimens, and building up anticipation, before stepping up and taking a long, intense look at this tall drink of water.

Go see the elephant. If you know basic anatomy, look at its leg muscles. Check out the huge triceps, still attached to the elbow; I like to say it is the size of a graduate student. Same for the analogous superficial gluteal and somewhat-fused biceps femoris muscles on the rear end, around the thigh/knee joint. Huge! I’ve never been able to view a standing dissected elephant, so this really impressed me more than a table full of giant muscle slabs like I normally deal with. And best of all, for me, the “false sixth toes”; the prepollex and prehallux; are visible in all four feet (but not noted anywhere, even in the book; too bad, these things were widely known by anatomists before my work on them). So much to marvel at here. It is an anatomical treasure. I wish I had a 3D image of it to use for anatomical studies- it was so easy to identify every single muscle group (except for a few missing around the shoulder/neck), even in the distal limbs. Hmm, photogrammetry might be possible (nugget of idea begins to crawl around John’s brain like a Zimmerian parasite)…

Behold, the triceps muscle of an elephant!

Behind that gorgeous elephant, don’t miss the wall mountings of two cross-sectional slices: through the head/neck of a moderate-sized elephant (How!?!?) and distal leg (no predigits but good features). And definitely don’t miss the stool (non-fecal, furniture form). I almost did. A wooden stool is shaped like a newborn elephant and a cross-section of the body is adhered on top of it. I assume you cannot sit there, and I am very glad that it was not, as I first imagined, an actual plastinated baby elephant turned into a stool. That would be bad taste.

The exhibit is in very good taste, without exception, and although I am gore-desensitized to say the least, it is not gory in my view. The plastination process preserves the reality and even some of the colour faithfully, but renders it just unreal enough (past uncanny valley territory?) that it should not be very disturbing to most viewers.

You can’t leave with your own photographs, but you can be schnookered into buying the exhibit book (£12.99) and a couple of packages of nice colour postcards (£4 for six; excellent quality images and cardstock IMO). The book and postcards show many of the exhibit specimens but not all, and include some others that are not on exhibit. I was saddened that the bear was left out—very cool image of that in the book. I’ve only skimmed the book a bit. I was annoyed by a few mistruths about elephants (25mph running speed, “have no ankle joints, which is one of the reasons why elephants cannot jump”, the bones “do not contain any marrow”—wrong, 15mph and there are ankles, they just are not very flexible (but not immobile either); also the bones do contain marrow (how could a large vertebrate survive entirely without it???) but just not as much of it per unit volume, due to lots of spongy bone). But I am still very happy with the 139 pages chock fulla pretty images, which is all I really wanted. Indeed, the book is a great pictorial anatomical reference- some of the species such as elephants and giraffe lack a really good anatomical resource in the modern, or any, literature! The exhibit shop also sells some good anatomy texts, mostly on humans but I recommend “Animal Anatomy for Artists” very strongly; I use that regularly in my own work.

So, £29.99 of schnookering later (haha, poor victimized me!), I emerged and reflected more on what I’d seen. I’m still a bit giddy about it all. I like the minimalism in most aspects- black backgrounds, minimal signage (but just enough to make it educational—when they got the facts right), focus kept on the specimens. Well done there. The spectacle of the specimens I’ve raved plenty about- it is not at all disappointing. It is AWESOME in every sense. I feel I easily got £9 of value from the ticket, and would (probably will!) pay it again. It is a profound experience to see the rich anatomical detail exposed, and be able to circumnavigate the specimens to absorb multiple perspectives. If you know some anatomy, you’ll be doubly rewarded at least, and if you bring your own phylogenetic perspective that can be trebled.

Baby white rhinoceros. Sad infant mortality.

What makes me happiest after my visit is realizing that we are in an anatomical renaissance for science and public interest therein. Exhibits like this and documentaries like “Inside Nature’s Giants” have tapped a public interest and curiosity in the wonders of basic anatomy. Anatomy is at the core of so many biological sciences and is so immediately accessible to people, because we all have anatomy. Anatomy is at the crossroads of art and science; it is visual, variable and complex, yet concrete, objective and easy to relate to. “Animal Inside Out” is a spectacular blend of art and science. They nail the artistic aspect, and the science is done reasonably well (despite my few gripes)—the exhibit’s science speaks for itself, in a way, although many visitors will need a nudge to grasp that.

I’d like to make a call for a permanent exhibit of the likes of “Animal Inside Out” in the UK. We deserve this! Museum exhibits could use something new, other than lame, quickly broken digital pushbuttons and bland skeletons devoid of soft tissue context (although the latter can be sufficient, e.g. at the Paris NMNH). That’s what makes “Animal Inside Out” (and Body Worlds) such a hit- as Hagens is quoted on the book dustcover, animal anatomy that goes beyond digitized abstractions and dusty bones is able “to sharpen our sense of the extraordinary by looking at the self-evident.” I could not say it better myself. This exhibit is extraordinary; that is self-evident after even a peek. It is a loving tribute to how fantastic the totality of animal structure is. Go! Enjoy. Absorb. Gape. Stare. Thrill. Revel. Think. Question. IT’S BEAUTIFUL.

Impressive hippo mouth says “Farewell for now.”

Edit: @samjamespearson on Twitter has kindly posted some photos (for free NHM/AIO publicity) of the exhibits and here are the links, now that they’re out there– SPOILERS! And thanks, Sam! I don’t think these really spoil the intense visual experience of actually being there and walking around the specimens, not at all.

octopus, whelk, squid, needlefish, scarlet haze of shark, hare brain, cat nerves,  bactrian camel, another camel,  bull (I forgot to mention it; this one was pretty great!)

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How to Turn an Elephant Hindlimb Into a Biomechanical Computer Simulation

Posted in Geeking Out, tagged , , , , , , on May 16, 2012| 18 Comments »

This post will walk through the basic steps we take to do some of the major, ongoing research in my team. It comes from our lengthy project aiming to determine how elephant legs work at the level of individual muscle/tendon/bone organs. We need fancy computer simulations because anatomy, mechanics, physiology, neural control etc. are all very complex and not only impossible to completely measure in a living, moving animal but also extremely unethical and unjustified in the case of a rare, fragile animal like an Asian elephant. We want to do such complex things to test hypotheses about how animals work. For example, we want to estimate how fast an elephant could run if it wanted to, or why they cannot (or will not) jump or gallop like smaller mammals do— even as baby elephants (~100 kg or 220 lbs), which is an ancillary question we’re tackling. That’s cool basic science, and that’s enough for me. But the applications once such models and simulations are established are manifold– human clinical research now routinely employs such approaches to help treat “crouch gait” in patients with cerebral palsy, plan corrective surgeries, aid in rehabilitation strategies, and even potentially optimize athletic performance. Non-human research is pretty far behind this kind of confident application, because there are too damn many interesting non-humans out there to study and not many people using these approaches to study them (but it’s catching on).

Breaking up the monotony of the text with a baby elephant we met during our research in Thailand (Chiang Mai, here) in 2001. It was just a few days old and VERY cuddly and playful (chewing on everything!) but it’s mother did not want us playing with it so we only gave a quick hello.

I use the term model to refer to a simple abstraction of reality (such as an anatomically realistic computer graphic of a limb), and a simulation as a more complex process that is more open-ended and generally uses a model to ask a question (such as what level of extreme athletic behaviour a modelled limb could support). We use models and simulations to test how all the structures of the limb work together to produce movement. This also reciprocally gives us insight into the question, as I like to say it, of why is there anatomy? What is anatomy for? Why does it vary so much within so many groups and not so much in others? This can more easily be addressed by focusing on the consequences of a given anatomy rather than the more tricky question of why it evolved.

These approaches also can answer the frightening question of “Does anatomy really matter?” Sometimes it does not. And those “sometimes” can be impossible to predict- although sometimes they can be easy to predict, too. I think we are not at a point in the maturity of biomechanics/functional morphology to usually know a priori when either is the case.  Many factors in addition to anatomy determine function, behaviour, or performance; that’s why; and biomechanics aims to unravel those relationships. A lot of anatomists, palaeontologists, etc. assume that form can be reliably used to predict function, but plenty of studies have shown already (and if you peer deeply into the details, it comes from first principles) that one cannot be sure without either measuring what anatomy is doing in a particular behaviour or estimating that function in a computer model or simulation.

Anyway, I’ve covered my perspective on this in a paper which you can read if you want to go into deep philosophical details of the science (and read me blabbering on more about this particular hobby horse of mine?). This post will proceed mostly with pretty images and simple explanations, although I welcome comments and queries at the end. As part of this post, I’ll try to give an idea of the timespans involved in doing the research. Some steps are quick and easy; others can take dauntingly long — especially to do well, without building a digital house of cards.

I’ll start, as my posts often do, with a deceased animal, and in this case it will again be an Asian elephant. Incidentally it is the same animal from the “Inside Nature’s Giants” series (see previous post).

Above: the hindlimb viewed from the rear, showing the medial (inside) region of the thigh skinned down to the superficial musculature. The hip is toward the left of the screen, and the knee is to the far right (whitish rounded area), with the shank (still bearing most of its grey hide) heading to the bottom right corner of the picture. Muscles pictured include ST (semitendinosus) and SM (semimembranosus); major hamstring muscles; as well as the thin, sheet-like gracilis, the straplike sartorius, and the massive adductors toward the top of the image.

When collecting data from dissections for functional analysis including computer models and simulations, we dissect the muscles one by one as we identify and photograph/sketch them, then remove them and do a suite of measurements to characterize how their form relates to some basic functional parameters. From the mass (weight) of the muscle and the length and angulation (pennation) of its fibres (bundled as fascicles) we can estimate what is called the physiological cross-sectional area (PCSA) of each muscle, which is known to strongly correlate with the force the muscle can produce. Different muscles have different PCSAs; for example check out these pictures of a long-fibred, lower-PCSA muscle and a short-fibred, highly pennate and high PCSA muscle:

Above: the long muscle fibres (bands running from left to right, somewhat diagonally from the bottom left corner toward the top right) of a hip adductor muscle in our specimen. The adductors are fairly simple muscles that run from the underside of the pelvis to the inside of the thigh (femur).

Above: the tensor fasciae latae (TFL; pretty sure of ID but going from memory) hip muscle of our specimen, cut open to show the short, angled fibres (each leading at around a 45 degree angle to attach onto a thick central internal tendon). The TFL is just out of view at the top of the screen in the whole leg anatomy picture above; it is on the front outer, upper margin of the hip/thigh and runs down to the outer side of the knee, invested with thick sheets of connective tissue (fascia).

The maximal isometric force (Fmax) of a muscle is computed as the PCSA times the muscle stress (force/unit area), which is fairly conservative in vertebrates. A square meter of PCSA can produce around 200-300 kilonewtons of force, or about 60,000 cheeseburger-weights (the standard unit of force on this blog). That’s a lot of quarter pounders! And an elephant has pretty close to that many cheeseburgers worth of leg muscle (around 150 kg mass, very close to a square meter of PCSA; total Fmax would be around 80,000 cheese-burger weights!). That much muscle is important because an Asian elephant like this one weighed 3550 kg or about 9000 cheeseburger-weights. So if all the muscles in one elephant hindlimb could push in one direction at once, in theory they could hold about 9 elephants aloft. However, as the picture above shows, they do not all act in the same direction. Furthermore, there are many other factors involved in determining how hard a leg can push, such as the leverage of the muscle forces versus the actions of gravity and inertia (mechanical advantage). All those factors, again, are why we need computer models to address the complexity. But the end result is that elephants cannot support 9 times their body weight on one hind leg.

Enough talk about cheeseburgers and enough possibly savory pictures of giant steak-like leg muscles. I don’t want to be blamed for hunger-induced health problems in my beloved blog-readership, dear Freezerinos! The above steps take about a week to complete for 2 legs of a big elephant, rushing against decomposition to try to get the best quality data we can. On to the digital stuff- let’s turn the geekitude dial up to 11 with some videos of computer modelling.

Our next step, often featured on this blog because I do this so often, is to take CT (and/or MRI) scans of the specimen that we wisely did before we cut it to bits, and use those to make a computer model. That’s the easy step; a scan nowaways takes me less than an hour to complete, including moving the specimen back and forth between the freezer and imaging centre. MRI scans can take quite a bit longer. Here is a CT scan of a similar hindlimb (right leg for the toes up to the knee, from a juvenile elephant; the above leg was too big for our scanner!). See what you can identify here:

And then here is a resulting computer model of the same animal (just knee down to toes), showing how we took each CT slice of even the muscles and turned them into fully or partially 3D digital organs, in our case using commercial software that makes this procedure (a step called segmentation) very easy:

The segmentation step for bones is usually incredibly simple; it can take anywhere from an hour to a day or so, depending on anatomical complexity and image quality. For muscles, this is harder because the images are often more hazy and muscles tend to interweave with each other, segue into tiny tendons, take sudden turns through bones or other narrow spaces, or even fuse with other muscles. So when we do this kind of musculoskeletal modelling, it gets pretty laborious, and can take weeks or months to finish.

Ahh, but once you’re done with the basic anatomy, the real fun begins! We take the 3D images of bones, muscles, etc. and import them into our biomechanics software. We use two packages: one commericial item called SIMM (Software for Integrative Musculoskeletal Modeling) for making models, and a nice freebie called OpenSim for doing simulations (although actually we’re finding SIMM is often better at doing both modelling and simulation for more unusual animals). Quite a bit more anatomical work is required to get the joints to move properly, then position the muscles in accurate or at least realistic 3D paths (depending on segmented image quality), then check the muscles to ensure they move properly throughout the joints’ ranges of motion, then import all the PCSA and Fmax and other data we need from dissections, then do a lot more debugging of the model… this takes months, at least.

But the greatest joy and pain comes in getting the biomechanics done with the models and simulations. You can get quite simple data out of the models alone; such as the leverages (moment arms) of individual muscles and how these change with limb joint position, across a gait cycle, etc… That’s pretty interesting to us, and can just take a few days to crank out from a finished model. Yet the ultimate goal is to do either a tracking simulation, in which we make the model try to follow forces and motions that we measured in experiments from the same or a similar animal (standard, harmless gait analyses), or a theoretical simulation, in which we set the model a task and some rules (‘optimization criteria’) and then set it to run (for hours, days or weeks) to solve that task while following the rules. In both cases, the simulations estimate the muscle activation timings (on/off and intensity) and forces, as well as the kinematics (motions) and kinetics (forces) of the limbs. Then we check the results, play around with the inputs (unknown parameters) as part of a sensitivity analysis, and re-run the analyses again, and again, and again… Here is a draft of a tracking simulation we’ve run for our elephant’s hindlimb:

Above: again, a right hindlimb of an Asian elephant. This test of our tracking simulation is replicating real experimental data (from motion capture and force platform analysis) of an elephant running at near its top speed; over 4 meters/second (>10 mph/16kph). The red lines are the individual muscles, and the green arrow is the ground reaction force, equal and opposite to the force that the limb applies to the ground. In a fast elephant that force can exceed the elephant’s body weight, so the muscles need to crank out kilo-cheeseburger-units of force!

And that’s about as far as I’ll get today. My team’s previous research (explore links for some fun videos) has shown that elephants can run about 7 meters/second (~15mph; 24kph) and that they have pretty poor mechanical advantage when they do run, so their muscles must have to work pretty hard (about 6 times more cheeseburger units in a fast run vs. a slower walk). So how do they do it? And what prevents them from going faster? What would happen if they jumped? What limits speed more; muscles, tendons or bones? Stay tuned. I’m still not sure how much longer this final step of the research will take… (presumably will precede the heat death of the universe by a long shot) But overall, the whole process when everything works nicely can take a year or so to do, proceeding from whole limbs to a simulated limbs.

As a final teaser, here is work we’ve done on using a different kind of model, called finite element analysis (FEA), to estimate how many cheeseburgers it would take to break an elephant’s femur (thigh bone), for example. How “overbuilt” are bones vs. muscles or tendons? This is still a poorly resolved question in biology. We’ve established some rigorous methodology for doing this, now we just need to see what answers it gives us…

(the colour shows the strain (deformation) in the bone in a simple bending experiment; “hot” colours are higher strain. The visualization of the strain is greatly exaggerated; in the real results they are barely visible, as bone only bends a tiny amount before fracturing)

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Oh hai, Boing Boing!

Posted in Frozen Mammals, tagged , , on April 26, 2012| 6 Comments »

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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Inside Various Giants (A Pictorial Retrospective)

Posted in Croc-cicles, Frozen Mammals, tagged , , , , , on April 13, 2012| 31 Comments »

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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The Tragic Frailty of Elephant Feet

Posted in Frozen Mammals, tagged , , , on March 30, 2012| 5 Comments »

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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Out of the Freezer and Into the Loading Jig

Posted in Mad Science, tagged , , on March 16, 2012| 6 Comments »

Well, it’s time for the Grand Reveal of what the picture in the previous post is (reproduced below). The guesses ranged from bird to wallaby/kangaroo to the stuff of nightmares. And indeed Nick Gardner got it right first, it is a wallaby. Specifically, it is a Bennett’s Wallaby (Macropus rufogriseus rufogriseus), which is the Tasmanian island form related to the Red-necked Wallaby, and an animal that has gone feral (along with mara and other cool critters) in Whipsnade Zoo near the RVC. You can tell it is a wallaby and not a bird, because there is an “Achilles tendon” attaching to a calcaneal tuber (“heel bone”) on the back side of the limb (shown with asterisk below) that birds lack, and if you look closely the toes are hairy, lack bird-like claws, and a few other details like the profile of the musculature are very different; more mammalian than avian. The stump of the muscular tail (cut off) is also a clue. Although the avian similarity in the case of wallabies is still striking, which is one reason I chose this image. Well done, Nick!

I found this picture in my archives and remembered when it was taken back in ~2005- some lab members received some frozen wallaby legs and thawed them out to use in experiments. They tried to compress the legs in an Instron machine (mechanical testing system; partly visible at the top of the pic) to see what the passive, springlike properties of the legs are like in a wallaby, vs. the properties they could measure in a living animal. (The shiny white reflective areas in the pic are for tracking joint motions) And I thought it was a freaky cool pic, so I shared it.

I also posted that pic because my team has done some in vivo analysis of the leg properties in such animals (previous news story here; paper in preparation), and because we use this technique of loading cadaveric legs in such machines quite routinely. We did this for elephant feet to study how the “sixth toe” of elephants works, and we’re analyzing data (as I write) for how elephant feet and rhino feet deform or move when loaded similarly. This method has a long history; we didn’t invent it; perhaps most famously used for studying horse limb mechanics [pdf example], which have a lot of passive properties (almost everything below the elbow/knee is non-muscular). Many animals’ limbs are tendinous/elastic toward their distal end (toes), so the limbs tend to become less actively controlled by the nervous system and become more of a mechanical control system (sometimes involving a non-neural “preflex“) in that region; although it’s all a matter of relative degree of passive:active control in different situations, species, and limbs.

The picture below shows an x-ray of an elephant’s whole hind foot, in which you should be able to see the bones (brighter white) of the foot surrounded by a lot of soft tissue, mostly more passive kinds like fat, skin, fascial sheets, ligaments and tendon.

Here (further below) is a preliminary image from our elephant foot studies in progress, intended to reveal the passive properties/motions of the feet so we can figure out how those properties are combined with more active control, and how actively elephants control their feet vs. other, possibly more ‘passive-footed’ animals like horses. This is interesting from anatomical and evolutionary perspectives, and for helping with foot health problems that are serious concerns for such animals– more about that later. The arrow in the picture below shows where a lot of the motion is: at the knuckle (metatarsophalangeal) joints of the toes; the rest of the foot tends to rotate around these mobile joints. We can’t peer inside living elephant feet to see if they actually do this, but we can compare the external motions, pressure patterns, and other data from living and dead elephant feet to see how they match up, which is what we’re doing now — and we’re doing the same thing with rhinos, which have cool 3-toed, more “hoof-like” feet, as opposed to the 5-toed, fatter feet of elephants. To get this image, we’ve had to put the foot inside a custom-made device using a car jack to apply a constant load, and a wooden framework to hold the specimen still, and then run it through a CT machine in unloaded and then loaded states to see how the bones move. Here is what the crazy apparatus looks like, with enthusiastic undergrad for scale:

This, below, is a right hind foot (pes) of an Asian elephant, shown from the inside of the foot (toes are numbered 1-4 from the big toe/hallux toward the outside of the foot; 5th toe is not visible). The yellow image is the relaxed, unloaded foot; the green is after applying a large load equivalent to the animal standing on one foot (or running quickly). Notice how the third metatarsal (the long bone that the arrowhead is touching) for the unloaded state is in front of that for the loaded state, whereas yellow and green images of the bones toward the tip of the toes are overlapping more, indicating they did not move much/at all. That tells us that the motion is occuring at the joint indicated (“knuckle”), which makes sense anatomically, because that joint looks like it has a lot of mobility.

Image

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Six-toed Elephants?

Posted in Frozen Mammals, tagged , , , on March 11, 2012| 14 Comments »

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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