Structural anatomy geek-out: BODYWORLDS

I’m surprised to realise that I haven’t written here since 15th December. That’s an unheard of amount of time. 

Things were busy before christmas, obviously, and they will continue to be busy for a little while longer. My aim to finish another corset or two whilst at home didn’t work out due to a horrid chest infection that has worn me out. I insisted it was just a cold for a while, but the sodding thing just got worse and worse. Had no voice for four days. John entertained himself by asking me to sing power ballads, which was quite funny as I had no pitch control whatsoever and am not exactly a singer in the first place… Am nearly over it now though.

I did get a few more Pegasus drawings done. Far less demanding than corsetmaking. Met a couple of new piebald ponies in the field behind our house, and spent a good amount of time chilling with mum’s dog Poppy, to help her continued development in terms of learning to trust humans. She’s coming on so well, it’s nice to see the changes each time I visit. 

First couple of days back on the boat, we didn’t have electricity. It’s a recurring problem, we think that water gets into our meter on the towpath and trips it off. It’s just been sorted this afternoon, thankfully, hence my ability to charge the ipad and write to you all. With the electric off though, we decided to sleep on the futon in the main room. I think the bedroom would have been fine, but without use of the electric blanket it seemed as good an excuse as any to finally test out the futon. It’s quite comfortable to sleep on. Really firm, but I like that. Soft mattresses tend to make me sore. But so I haven’t quite felt like I’m back in my own environment yet. I reckon tonight will be back to normal though. And, in happy news, Cat is back from the cattery! So that makes it feel like home. 

He wondered around looking startled and inspecting everything, as usual. Popped his head into the cosy “cat igloo” mum gave us at Christmas, jumped on and off the boat through all his various entrance points, was chased by a dog, shouted at us with the “foreign” accent his always gets at the cattery, then eventually began head-bumping and singing and demanded cuddles. Very sweet. 

Anyway, with this chest infection I’ve been cracking on with life but been a bit out of it for the past two weeks. Need to sit down and do some writing and planning in the 2017 diary. Need to re-focus and figure out a timeline for finishing the last bespoke orders. Need to check up on my accounts and pay a few bills. Need to tidy the boat, do laundry, and just generally sort out my life, haha. Need to not get distracted by fun things (ponies) at the expense of all those other important tasks… 

Oh, New Year’s Eve! For the evening I stayed at my mum’s and chilled out with a jigsaw, lovely peace and quiet. But in the daytime, I met up with a friend in Newcastle and we went to the “Bodyworlds: Animals Inside Out” exhibition at the Life science museum. It was brilliant! I’d thought there’d be maybe one equine exhibit, but in the end there was many. One skeleton, three heads, one foal, one brain, and a few images showing cross-sections of heads, legs, etc. It was super interesting, and the high number of other quadrupeds gave lots of framework for comparison. I’m very much at the beginning of learning about equine anatomy, but it’s very much with a view to understanding the biomechanics of healthy movement and so comparative anatomy is interesting too. I suppose I should write down some of my thoughts here. 

Let’s start with a silly one… How can so much stuff fit inside one body?! The display of the three heads showed one with musculature and some skin/hair, one of the blood vessels, and one of just the skeleton (skull and some cervical vertebrae). The middle head, the blood vessels, included even the tiniest capillaries whereas most of the specimens showing blood vessels didn’t for the simple reason that they were so tiny, numerous, and densely packed that to the human eye they almost look like a solid structure in themselves. You can’t see through to the bigger vessels beneath. Along with intestines, villi, rumen, and so on, in all the different types of beastie, all I kept thinking about was how everything is to do with surface area. Maximising available space. 

When looking at the horse skeleton, we both sort of laughed and the first thing my friend said was, “no wonder they’re on the forehand.” In terms of bone, the weight is very much there. Huge bloody head, big old ribcage hanging between the front legs (and only supported by soft tissue, there is no bony connection to keep the ribcage lifted and alleviate the weight on the front legs), and a pelvis that looks comically small by comparison. Who knows what life this neddie had though. I was watching racing on TV a couple of days prior and those horses for sure have bigger pelvises. Apparently dressage horses tend to a longer pelvis too, which makes sense when you think of the leverage and tucking required. The hock isn’t a big joint and the thoracolumbar spine doesn’t have the ability to upwardly “round”, despite the way a back looks “rounded” when it is carrying a rider well. Lots of that rounding happens at the lumbosacral joint (where the lumbar vertebrae meet the sacrum and pelvis), by tucking the pelvis/sacrum under and forward which requires relaxation along the back and tone in the abdomen. It requires that the base of the neck lift gently and that the ligaments provide support so that the right muscles have a chance to develop. Ie: that the horse be allowed to reach into the bridle and that specific movements are used to slowly strengthen the body so that it can maintain that posture under rider. 

Seeing the atlas and axis (first two vertebrae of the cervical spine) made some things obvious too. I had already learned why you don’t want to overbend the neck… the atlas-axis joint can only really hinge side-to-side, so if the poll resists or is so flexed that any further flexion travels backwards, it will bend excessively between the axis and C3. This is the “broken at the third” that people so often point out in dressage horses that may have been trained insensitively, though I’ve seen it even out at small shows too. But when you see the actual bones in front of you… the shape of the upper edge of the axis is such that if you imagine the neck over-bending you can really see how the nuchal ligament that runs along the top of the neck will be pressed taut against these bones creating unwanted and uncomfortable pressure. At the poll, all through the back… I believe this is sometimes the deliberate argument behind Rollkur, that by over-stretching the nuchal ligament you put the connected ligaments along the thoracolumbar spine under tension, thus raising the back and freeing up the movement muscles. But it doesn’t work, as the back is over-braced, the pull on the LSJ area is too great, the pelvis can’t tuck underneath and the hind legs are thrown out to the back. It’s obvious in Rollkur, but it happens in a smaller way with even mild overbending. 

It was also really clear why overbending (or trying to demand poll flexion as an active process rather than passive outcome) gives a neck that is pretty and round at a glance, but short and ugly when you look more closely. That gentle S shape to the cervical spine is sort of reciprocal. Poll flexion happens between the occipital bone and the atlas, it doesn’t actually happen in the cervical vertebrae but at the end of them. If you bend longitudinally through the actual vertebrae they compress into a more dramatic S all the way from C1 to C7. The neck looks round and pretty at the top, but it has dropped/compressed just before the ribcage. The extreme visible result of this is a dip in front of the withers at the neck. With the weight of the head supported by a compressed neck, the wrong muscles are working and/or sometimes the rider’s hands is holding up the head. If the horse is supporting his own head whilst over-flexed and unfit, he is doing so by compressing so that the weight travels backwards. And where does it stop? At the wither. The dipped C-spine at the base of the neck and dropped ribcage puts the weight more through the forehand than it already was. Then the back often hollows too and though the horse may be “on the bit” in terms of his profile being near-vertical the rider feels like there’s nothing between their legs and the energy doesn’t come through. I’ve been reading about this stuff for a while now, watching lots of living, moving animals in a bid to improve my eye and trying to pay attention whilst riding myself, but with a skeleton right in front of you, you can see it quite clearly. The progression must be: on the forehand… in an horizontal balance… weight carried behind (if you ever take it that far). The look of the raised and round neck is a consequence of lowered haunches, a tucked pelvis, and an elevated ribcage. It’s the end point and a consequence of overall body development. Starting with the neck/head instead of ending with it, gives the opposite result, putting the horse more on the forehand, not less. All easier said than done, naturally, but so fascinating to learn and see more about how they move and how challenging it must be asking them to carry a rider whilst also changing their balance and musculature. 

The foal was very interesting too. He had his skin off and I think we were looking at the most superficial layer of muscles. It gave a real sense of how the brachiocephalic and latissimus dorsi (amongst others) really are for movement more than posture. When you get that thick underneck from forced poll flexion (where the horse pulls his nose in rather than letting it hang from the poll passively) it is often combined with high knees (connected to this overuse of the brachiocephalic, etc.) which look flashy but are part-and-parcel of an extended rather than flexed back. Which is arguably fine, if there’s no rider or weight sitting on top. You can see how the lower limbs are all tendon and ligament, so the movement comes from higher up and uses stored elastic energy rather than constant muscular effort, which is very economical. But if muscles like the latissimus dorsi are compromised (for example, by taking on more of a postural role than they are meant to, or by bracing against discomfort), you’re going to compromise the limb all the way down. The trapezius is rather thin, which I’d read about a few months ago in an article by Gillian Higgins of Horses Inside Out. So when they talk of hollowing at the thoracic trapezius it is indeed at that site but it isn’t of that muscle. It’s the muscles beneath. Atrophy there is going to be a problem for the front limbs and the thoracic sling muscles, weighting and restricting the forehand further. With the foal and his huge old head, you really see in an exaggerated way how much strength must be required in the hind end (and how much tone in the thoracic sling) to elevate the front end safely in pirouettes and the like. Now imagine it in a grown horse with a longer back, heavier guts, a rider on board, and thus more weight to balance! No wonder short-coupled baroque breeds are said to have an easier time collecting. 

The cross-section images were also interesting. With all of these beasties we really wanted to know why and how they had died, but that information sadly wasn’t given. Were they examples of animals with reasonably normal and healthy structural anatomy? How precisely were their parts pinned back together? My friend (who has a brilliant eye for horses) reckoned that our slightly cow-hocked skeleton probably was likewise in real life, but with the display sitting slightly wonky my eye wasn’t good enough to tell. 


Oh, another well-illustrated point… the mandible! When you look at the lower jaw of the skeleton it is neatly illustrated just how thick the masseter muscle really is. Makes sense, if we spent 18 hours a day chewing we’d probably have thicker cheek muscles too. When we then looked at the head with muscle still attached, the masseter on one side was thicker than the other, suggesting preferential chewing. Sore tooth? Something else? Discomfort or asymmetry in the jaw or TMJ is going to have a knock-on affect through the whole body, so asymmetric masseter muscles are interesting. 

There were many other mammals too, of course, a couple of rabbits which was interesting since I remember reading as a child that horses began their evolutionary journey as something more rabbit or deer like. Smaller, with more flexible spines and multiple toes. When their environment changed so did they, and the main change was food. Thus the need for a massive digestive system. And thus the need for a very sturdy, reasonably inflexible, spine. A strong framework to hang all those guts from. 

When you looked at the goats and reindeer in the exhibit, you could begin to see the consequences of their environmental differences. The reindeer seemed somewhat similar to the horse, but the mountain goat was far more lean and athletic. I wish I’d taken a picture. The raised spine along the goat’s scapula was far more pronounced than on a horse. The projecting bone at the back of the hock, likewise. I’m guessing it’s all about leverage. The greater projections give more sites for muscles to originate and insert. More sites (or just larger attachments in the one site, if you see what I mean?) must give more strength or more control. More leverage. More athleticism for the mountain goat so that he can leap and balance in ridiculous places. Like a racehorse with his long pelvis for huge rear end muscles to anchor to and create that forward thrust of power. 

A nice thing about the reindeer was they were shown at speed. Deer’s lower limbs seem to be longer and more elegant than the short cannons that we really want in working horses, and perhaps this is part of their different gait. They seem to leap and bound, and the closest a horse gets is perhaps jumping or galloping, with the hind legs coming right forward and underneath almost as a pair, and the LS joint doing a lot of work. But I have fewer connections/thoughts to make on that, as I’ve not moved beyond basic structural anatomy into gait-specific info yet. 

We saw many hearts in the exhibition. A cat’s heart is so tiny. I told John afterwards and he asked if instead of the usual chambers a cat’s heart is split equally down the middle into “love” and “hate”. I like that idea. 

So my NYE was pretty sweet, despite the snotty nose and coughing. Am now really looking forward to the equine dissection I’m attending in April, but have a lot of learning to do before then if I’m going to really understand and enjoy the knowledge shared there. Not yet though. There’s a lot of work-stuff to do and I need to not get distracted. That said, I’m not working this week. I’ve not given myself enough of a chance to get rid of this chest infection and it’s lingered too long. Am determined to see the back of it now! 

Anyway, Happy New Year everyone. I hope 2017 brings a lot of curiosity, kindness, and contentment for you all. 

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