Transcript for:
Understanding the Horse's Skeletal System

okay so in this lecture we're going to talk about the H's skeletal system so we'll do um for those of you that have taken ecoin science one and ecoin Science 2 this will be a much more comprehensive overview of the H's skeletal system um and so let's Jump Right In um to the function of the skeleton um so the skeleton has six primary functions so um this is definitely something I could ask you on exam and it's important that you know in this class in a class that's focused on veterinary medicine we're aware of the different parts of a horse but also the the purpose behind those different structures so that um we can kind of wrap our minds around you know why a vet may do a certain procedure or why you know why an issue with a bone could actually affect something else and vice versa um so it may seem like we're kind of going in very detailed and then we'll kind of pull it back and look at the big picture of it all let's start with these six functions so um number one the skeleton is there to protect internal organs so um on our horse here we can see our rib cage and that is protecting right the horse's heart the horse's lungs its digestive tract um and even um a little bit of the reproductive tract as well you can see these ribs come all the way up to um the shoulder all all the way through almost all the way um to the hip so there is a space here we'll look at that more here in a minute but the rib cage really serves to protect the internal organs there and then of course our skull is protecting the horse's brain and then the vertebrae are protecting the spinal column so um there's just the first one I don't know what else I was going to add to that and then number two um the skeleton actually actually stores and releases fat um so there is some fat in inside um Bones on the horse or in all animals that have uh skeletons and so it can store and release fat and then we do we should know this right that um the skeletal system produces blood cells so the bone marrow in your bones um produces blood cells the skeleton also stores and releases minerals so it can store calcium and other minerals like that and then if the body needs um minerals for some process and it's not getting it enough in the diet um the skeleton can release those minerals um and so we'll see that sometimes like if fos are or any horse but we see this especially sometimes in fos that maybe aren't getting very good colostrum or very good milk from the mother um they can struggle with um a weakened skeletal system because the skeleton is trying to release the calcium it's not getting from the diet to make up for that um and then the skeleton this is what we normally think of it right as these last two is that the skeleton facilitates movement and it supports the body so the skeleton um is there it's the framework for the body right um but the interaction between the skeletal system and tendons and ligaments is what allows that animal to actually move and then the skeletal system supports the body right it's that framework um without the skeletal system our animals and us we would just be a big heap of soft tissue organs laying on the ground so the skeletal system is very important um this next slide just saying how many bones there are I will not ask you to memorize these numbers just for your own um knowledge that there are 205 bones in the horse um the vertebral column has about 54 there's 36 ribs they have a sternum down here we'll look at that more later there's actually 34 bones in the horse's skull and um and then and the thoracic limbs which would be the front legs and the back legs there's 40 bones so just to give you kind of an idea of how many bones we're talking about here it's about 205 some horses um like some breeds have less ribs than others but this is a good roundabout number um and so you can see that their legs hold a lot of the bones in their body and that's where we see a lot of um issues in the horse often is in the legs so talk about the the different types of bone so we have long bones and short bones um and these long bones they are what they sound like they're just longer than they are wide so an example of that that would be the Canon bone of the horse um and these long bones serve as levers and so the interaction between these long bones and different tendons and ligaments is what allows um the body to move and so it'll hinge at certain points or articulate certain joints um by hooking on to a long bone and then the muscle contraction will you know help that bone work as a lever and then these long bones also support the weight of the horse and are what provide Locomotion so they they do a lot and we see a lot of long bones in the horse's legs um starting up here um with our scapula moving all the way down we see that these bones are long baby and then we got short bones so short bones are there to help absorb concussion and so we'll see them in complex joints like the carpus Tarsus and fetlock the carpus is the horse's knee the Tarsus is the horse's Hawk and then the fetlock joint down here as well and we'll look at all these joints in more detail um and I'll show you guys um we'll kind of take a a look a comprehensive look at the horse's skeletal system once we get to the end of this lecture so we've got long bones and short bones those are easy and then we have have flat bones and irregular bones so flat bones would be like the bones um in the skull and the ribs so those are those ones that are taking care of that skeletal function number one of protecting the horse's internal organs and so flat bones serve that job so ribs qualify as a flat bone and so do uh the bones in the skull and then irregular bones are those that protect the central nervous system so those in the spinal column here and you can see why they're called irregular they are shaped really wonky we'll look at those um a little bit more as we move through here so we've got long short flat and irregular types of bones in our horse but let's talk about what exactly is a bone made of right um there's um lots of different parts to Bone and so this image of on the right will kind of go through and this is showing um the internal structure of a long bone here and some of the images I use are from horse images some are human images it's all the internal anatomy is the same um it's just um it's hard to find material that is like um specific to horses when it comes to like really specific Anatomy things so if you see a bone and you're like is that a bone on the horse it may be an image from a human bone um but the internal structure is the same um so we've got different types of bone even even within one bone So within this one long bone we have compact bone cancellous bone a periostium and a metaphys as well and so the compact bone is just the general term for the part of the bone that appears solid let me get my little guy out here so that would be this part of the bone and you can even see that here so it's this part it's what we think of when we think of bone right we think of something hard and solid um and so that is this part here that appears solid and then the cancellous part of the bone um is the part of the bone that's porous it has visible spaces and so you'll see that here as we get closer to the bone marrow and so cancellus bone and spongy bone are synonymous same thing and so you can see it here um towards the middle of that bone and then also on the ends of the bone we have that cancellus or spongy bone as well um and then the periostium is a protective tough membrane um that covers the outside of the bone so you can see here it's it's just like a little um protective membrane that goes around the bone itself and it does not have this periosteum at the points of articulation so the points the ends of the bone or where a bone attaches to another bone you don't see that periosteum that's just there um for the nonarticulating parts of the bone to protect the compact bone and then the metaphys is a growth plate and so I'll show you where it lies here and then I'll show you another image as well um but in horses generally the growth plates close at about five years old we'll look at an image here in a minute that kind of goes into more detail about what bones stop growing when um but we'll see that on the ends of the bone right so the bone is growing it's not growing from the center it's growing from the middle and or from the end excuse me and you'll have growth plates at both ends of the bone um so those are just some basic parts of our bone compact cancellus or spongy periosteum and the metaphys um or the growth plate um in the horse world we normally would say growth plate but you may hear um someone use the word metaphys as well so let's kind of just go to our image here and look at this all let's start from the center so in the very center of our bone we have the bone marrow then as we move out we've got spongy or cancellous bone then compact bone and then lastly that periostium that serves as that protective sheath to go around our entire bone and then if we look at the bone as a whole um we have this center part I won't ask you this the diaphus and the metaphys I mean I'll ask you the metaphys but the diaphus is just that Center shaft of the bone and then we have the metap and you can see here some of our directional terms proximal and distal in an exam or something I I won't ask you those terms but I mostly want you to be aware of what the internal structure of this bone looks like and then understanding that there spongy bone at the ends of Bones and um the metaphys lies here not quite on the ends of the bones but if you look at this image you can see the growth plates are outlined in Red so they're not quite at the very ends of the bones they lie right about here and that's where that bone will grow and build from there okay so if we keep talking about our bone structure we talked about what's actually on the bone itself um but then we also have cartilage um which isn't bone right but it works with bone um and we have cartilage all over our body horses do too you know in their noses and their ears um but when we're talking about cartilage in relation to Bones what I want you to be aware of is that um we have articular cartilage on the ends of Bones on those points of the bone that articulate or move and so what cartilage does is it adds a cushion to help cut down on the friction and concussion so think about if we have two like a um a hinge joint on a horse that's articulating and moving back and forth like this we don't if it's just bone on bone that's really going to grind and have a lot of friction there and also if we have like um the bones on a horse on the horse's front leg think about that Cannon bone on that horse that lower bone there it's taking a lot of concussion and pressure and if it's just bone on bone hitting each other that's going to be quite a bit of concussion and so that articular cartilage is there in between those bones to help diminish that concussion and friction that can happen there um and so this articular cartilage is attached to Joint surfaces or um between bones and there's three types of cartilage we have Highland cartilage elastic and F fibro elastic um in this lecture we're not going to get too into detail about the three different types but just know that there are three kinds of cartilage um and um and the purpose of cartilage so we'll see that a lot in um um horses that get injections sometimes they don't have um the cartilage in their Jo joints is starting to diminish um or weaken and so you can give horses um joint injections to kind of help with that and keep that lubrication and um cushioning there we'll talk more about injections later on in life but okay so ignore these words for a second let's just look here so we can see here even on this image we've got our compact bone kind of you can see this transitioning kind of from this cancellus spongy bone down into more compact bone and we but still see though that cancellus bone in the center where our bone marrow lies and then here this line here is our metaphys or our growth plate and as we move up in a way um we will see that periostium start to come into play here too um but what this slide is mostly talking about is some other structures we'll hear about um when we're talking about the skeletal system we're going to have a whole separate lecture on these three items ligaments tendons and synovial membranes but I want you to be at least aware of them so the difference between ligaments and tendons ligaments hold bones together so they attach bone to bone and tendons attach muscles to Bone so you can see here there's a ligament here that's attaching this top bone to the bottom bone here this is not an image from a horse um but this ment is um attaching these two bones together a tendon is like this this would be this connective tissue here that's connecting a bone to a muscle okay um so that's our difference there and then if we go back here to talk about our synovial membrane um what the sovial membrane does is it it surrounds the joint in a capsule and so what that does is it provides lubrication to the joint and so you can see that here um we've got this synovial membrane and then inside of the membrane there is sovial fluid as well um and so that again just helps with that concussion it helps with lubrication and so what you'll have here is articulating cartilage around the ends of the bone and then your sovial U membrane as well in between the bones um to again help with that concussion and help with the friction okay so now we went into a little bit on the different structures in the bone just to get an idea of what bones are made of and again in this class um we're not going to spend too much time on you know I don't want to get much more detailed than this image on bone structure just because the point of this course is to learn more about um kind of the real world application of these things and so we could spend a lot of time going into the science of bone and um you know how bone grows and all this stuff um but I more want you to kind of have a working knowledge of what a bone looks like the different parts of a bone um you know if a you're working with a vet and they mention the metaphys you're like okay that's the growth plate I know what he's talking about if he mentions a horse is having an issue with the cancellous bone you would know okay yeah I know what he's talking about there or if you guys work for sports medicine vets um or lameness vets and you hear them talking about injecting a horse in The Joint capsule they're talking about injecting a horse um in this capsule between the joints to put um artificial synovial fluid essentially in the horse's joints to help with articulation and reduce friction so um if you want more detail on um this stuff it's it's I mean you can do lots of Googling and get kind of to the really nitty-gritty science of it all but I like to keep things in this class a little bit more um practical I guess because it's easy to get kind of bogged down in the weeds okay so let's talk about the two different categories of a horse's skeletal system so we've got the axial skeleton and the appendicular skeleton so um you could be asked this on an exam um to identify you know which part of the horse's skeletal system is appendicular um or axial and so what helps me is appendicular appendicular sounds like the word appendage appendant means limb right and so when we think of the appendicular skeleton we're thinking of the legs of the horse and that would include the pelvis of the horse back here the axial part of this hores skeleton talks about the skull the spinal column the ribs the breast bone or the sternum and so it's the parts of the horse's um skeletal system that protect soft structures right the appendicular part of the hores skeleton it's not protecting a soft structure it's providing the framework The Locomotion The Leverage to move that animal around so we'll look at each of these in a little bit more detail so let's go in with our axial skeleton starting with the horse's skull and so if we're looking at the horse's skull we're talking about the bones in the face and the cranium and so the skull is protecting the brain and some sense organs right so our horse has the brain they also have sinus cavities in here um and um that is the job of the skull to protect all those different things that provide the horse with some sense organs and things like that and so some of the main bones will see on the horse would be the mandible right so that would be the horse's jaw down here the nasal bone and then the orbital socket or Rim um I could ask you on an exam perhaps to identify some of those structures um I probably won't do that till we get to like our Dentistry section because you know those three anyways are pretty easy to identify mandible jaw right nasal bone the one on their nose orbital socket the one that's around their eye um so it's pretty simple and then if we keep moving down on our axial skeleton we'll be talking about our um vertebral column and so um the H's spine is broken up into a few different sections here and so this image um shows four of the five sections of the horse is um spinal column and I'm just going to draw on here the fifth one that it doesn't talk about um G of loop it in here so it's not it doesn't on this one for whatever reason it doesn't talk about the cervical vertebrae that we have here okay so the vertial column runs from the base of the head to the tip of the tail so you can see it goes all the way down to the end of the hores tail the number of bones in a horse's coddle vertebrae kind of depends on the horse some horses have longer Tails than others um and so in the cervical part of the H's um vertebrae we have seven bones so if you hear a vet say C1 C2 C3 and so on they're talking about the cervical vertebrae and C1 we just start number one with the top and then work our way down in number as we go down the horse's neck and then the thoracic vertebrae there's 18 vertebrae here then we have our lumbar as we move behind the rib cage and the lumbar runs from the rib cage um to where the ilum attaches to the sacral vertebrae and so then we have the sacral vertebrae running back here essentially where the horse's hind leg attaches to where the tail starts um and then the coddle vertebrae then runs down and you can see this rain it's oops 15 to 21 vertebrae depends on the horse how long their tail is um and so um on an exam I could ask you about the different sections label the five different sections of the horse's vertebrae um if you're in veterinary medicine you know the H's back is often something that's talked about um or a third of all horses um have this condition called kissing spine where the top um processes their vertebrae rub or touch together and that can cause the horse a lot of discomfort and pain and so you need to be aware of the different sections um so again those are cervical running from C1 to C7 then you have the thoracic lumbar sacral and coddle and so in an exam what I would probably do is um label it something like this it might just be this exact image honestly just the words race and you just need to label the five different sections um to be aware of that again if you're working with a vet and they say I think this horse um has having an issue in their sacral vertebrae you need to be able to understand what part of the horse's vertebrae they're talking about so they're talking about this hind section of vertebrae that runs from the iliam back to the um start of the tail head so if we keep oh we keep kind of discussing here our oh my goodness gracious I'm getting old if we keep looking at um the sections of our vertebrae here just a little bit to know about um the different characteristics of each part of the vertebrae and so the cervical section of the H's um spine is the most flexible and so think about why um it's got a lot of connective tissue to attaching it from each cervical vertebrae back to um the top processes of the thoracic vertebrae and so um because it's kind of suspended like this it has a lot more freedom to move laterally um versus the thoracic part of the vertebrae here um this is over our rib cage right so there's not as much movement and then um fun fact the height of the spinus processes so the top part of these vertebrae is what gives us the withers on the horse so some horses um don't have very tall tops of their thoracic vertebrae and so um they may not have very high Withers of course the horse's body condition plays into that right you could have a horse that's um really fat and so the top parts of their vertebrae really aren't showing um but some horses just naturally the top spinous processes of their um thoracic vertebrae are just very tall and so it gives them a really high wither and then the lumber Lumber lumbar part of the horses uh um vertebrae have more movement than the thoracic parts or the sacral and we can see why right it's not as attached to as much so the lumbar vertebrae has a little bit again more flexibility laterally and also vertically and because it's it's suspended here um the sacral vertebrae I don't know if you can tell in this image but they're fused together and secured to the hips so um these vertebrae don't move they stay in the same place and then in our coddle vertebrae just a fun fact is the last vertebrae on the horse's tail it has kind of a pointy shape and you can feel that when you feel a horse's tail you can feel down and feel that kind of um pointier end of that coddle vertebrae okay so that's just a little short course there on the axial part of the horse's skeleton so just to recap that's our skull right and then our vertebral column and our ribs um and the sternum falls into that category as well so it's all things that are protecting internal structures as we move into the appendicular part of the horse to skeleton now we're getting into the part that actually moves our horse um and propels them forward so you'll see here in blue we've got that appendicular skeleton so it's just the bones and the horse's legs starting up here with the scapula working our way down and the same for the hind leg so um we'll look at these in a little bit more detail starting with the front leg so on here you're going to see a lot of words don't panic um and so a lot of times students see this image and they're like oh my gosh um we're just going to go through the basics of them so the scapula so that's this top part here think about your scapula on yourself right it's your shoulder blade so the scapula Works um as shock absorption and we'll go through later on into these joints right now we're just going to talk about the bones so we've got the scapula right the scapula is up here it's the horse's shoulder blade and it it works to help with shock absorption then as we move down we've got the humoris and so that's essentially the arm of the horse right and so um that articulates proximally top oh sorry I'm down here approximately up here right closer to the horse's body um with the scapula so it hinges here and it can move here at the scapula and also distally on its distal end with the radius in Onna and so what the humorist does is as it articulates it's what brings the leg forward and it also um has a part in shock absorption and then the radius is the main weightbearing bone of the forearm so um we'll look at an image here that kind of shows the horse leg but if we've got the horse's body coming here this is where we would see like the horse's elbow and then as we come down here's the horse's knee so like here's the H's chest running here or their their belly running here and so this radius is the main weightbearing arm of the forearm weightbearing bone of the forearm excuse me okay okay and then as we keep moving down um we have oh excuse me as we move here we have the Ola this is not a very good image I'll show you another one here in a minute to kind of show what exactly the ol looks like um but the olna is fused to the upper or proximal part of the radius and it's just a long thin bone that's used for muscle attachment so different muscles in the horse's leg attached to the Ona to help with Locomotion and then when we talk about the carpus or carpal bones we're talking about the horse's knee and so you can see here these little short bones remember we talked about short bones at the start of our lecture um we see short bones in the horse's knee or their carpass and so there's eight bones that are arranged in two rows you can see there's a row here and a row here so there's eight little short bones arranged right there um to make up the carpus joint or the knee joint and then the cannon bone as we move down is this large bone that runs from the horse's knee down to their fetlock and then we see this Tiny Bone here this little splint bone um and they're on either side of the cannon bone so I'm going to show you let me erase this real quick and so you sometimes will hear horses having issues with their splint bones um and so when they're talking about that they're talking about these little thin bones that go on either side of the horse's Cannon bone okay so you can see here here's those splint bones one here one here and then our Cannon bone here okay so then we're going to keep working our way down this horse's leg so this is um a horse's leg and it's facing us so if like we're standing right in front of a horse this is the view that we would get and so we've got our Cannon bone and as we move down um we're going to run into the proximal CMO so proximal right we're meaning closer to the horse's body and CMO is just um they're talking about these seesm moid bones and so if they a vet or someone says proximal sesm moid we're talking about these bones up here that make up the fetlock joint um and then as we work down we've got our our pastor joints or pastan bones excuse me and so you'll sometimes hear vets say P1 P2 and P3 and so when we're talking about P1 two and three we're talking about the long P turn here this is P1 the short P bone here is P2 and then P3 is actually our coffin bone here and we'll look at some other images L actually let me pull up one force P1 P2 P3 that's AOL image but it doesn't show yeah maybe how old am I there we go okay so here's that horse's fet lock right here and as we move down we've got that long past turn so that's P1 and then we have p P2 here and P3 is this coffin bone so in in this image it's kind of hard to tell how they're connected um but you can see here so these are just our three um fenes so we've got P1 P2 three P3 long PN short PN coffin bone um and you can see why they're called that right the long past is long that short pnn is short um and then our coffin bone kind of um it uh it looks different from the other two but it's still classified as a fallinks one and the coffin bone is porous fun fact okay so we talked about a second ago our proximal CMO up here part of our fetlock and then we have our distal so away from the horse's body CMO bones and that is referring to our navicular bone and so the navicular bone acts as a pulley system for the Deep digital flexor tendon and so we see here this tendon that runs down and this tendon runs down in a attaches to this navicular bone and so the navicular bone being attached to this deep digital flexor allows for when that flexor tendon uh contracts it will pull the horse's foot back okay that was a crash course on the front limb um it's always so when I do these lectures I'm always hesitant on how long to pause but between but this isn't a live lecture so if you're like that was a lot of of info pause and Rewind just go back and watch um you know back it up five minutes and rewatch that if you need to so here we've got our hind limb um and so when we're talking about the horses hind legs will start at the pelvic girdle and so that just essentially attach attaches the hind limb to the horse's spine at the sacrum remember we talked about that sacral vertebrae here um and so the pelvic girdle starts here and it's attached here and it's where the two hipbones on either side of the horse come together and then as we move down we've got the horse's femur and that articulates with the hip bone and disly with the tibia and I'll show you that here so that femur bone runs here let's go back to this image so this is the femur right we've got our hip here and we've got our femur down here and so that articulates up here and then distally with the tibia so let's look at this image here and I have some people ask like on an exam am I am I gonna expect you to like label an image like this no um I'll show you towards the end I'll we'll get to kind of something that shows a little bit um more like the highlights of the bones um and I'll you'll need to be able to identify that but I'm not going to ask you to identify the coxal tuber not in this class okay so then our femur runs here right we said it articulates so it moves up here and it also moves down here and then um the patella is the kneecap essentially so on your own if you reach down and touch your own kneecap the horse has that same type of bone it's just way up here higher in their leg than we would think um and this is the largest sesm moid bone of the body so they've got these type of Bones they've got sesm moid bones in their um lower down in their legs right like we just talked about proximal sesm moid distal sesm moid and then the patella is also a type of ssoid bone um high up in their leg and it's just um it's a bone that's in their stifled joint so if you hear a vet talk about the patella a lot of times in our minds we're thinking ah patella the knees um but in a horse it's actually up in the stifle joint and then as we move our way down we've got the tibia and this is the main bone of the Gaskin and so those of you'all that have taken uh horse eval you know the gasan joint is a place where we look for um musling in our horse this is going to be really pretty so our horse's body kind of comes like this right so um the tibia is this main bone that comes in this place this is this line here was oh crap this line here is not pretty kind of goes like this yeah that's a little better um kind of like that that's a little bit better um I know some of you are probably laughing like when are you going to stop drawing you're not good at it and so this articulates with our femur here and then as well with the Tarsus or the knee of the horse and then the fibula is up here and it's just like the Ola on the horse's front legs and then it's just a long thin bone that helps with muscle attachment and it's fused on this end distally with the tibia and then our Tarsus so our Tarsus is our Hawk um so we've got Tarsus in the front our carpus in the I'm sorry Tarsus in the back legs and our carpass in the front legs with that hores what we think of is the horse's knee those are the carpus joints up here and then in the hind leg that equivalent is the Tarsus or the hawk so remember we said the carpus the horse's knee has eight bones arranged in two rows this one on the hind leg has seven bones and the Tarsus serves to help with Locomotion and shock absorption okay kind of ran through all those bones um and again you don't need to know every single bone on this image you do need to be familiar with the bones I outlined here in the words and then um you know on an exam I could ask you to you know to identify all these bones um but we'll get kind of more specific as we move into other lectures about I'm more concerned that you know the bones essentially from like the stifle down um we'll talk about the joints I want you to know but I'm not going to um typically I won't ask them like identify the hip bone um but as we move down deeper into the leg I would ask you to identify like P1 P2 P3 and so on okay let me take a break take some coffee amazing coffee is so good if y'all don't drink coffee I 10 out of 10 would recommend okay let's talk about joints a little bit more so we kind of touched on joints earlier right so we talked about um this joint capsule right so this joint capsule is in between bones and um it serves to provide lubrication um to help reduce friction and concussion between joints and so we've got different um sections of this joint capsule and so we've got our articular cartilage here right remember we talked about that before that's attached to the Bone and then within that we've got this um sovial layer here that runs and that um is underneath the fibrous layer of our joint capsule so we got this kind of like tougher outer layer of our joint capsule this fibrous layer right to protect the sovial layer and the sovial layer um is more delicate I guess you could say and that's what holds inside the sovial fluid so we've got fluid and then sovial layer and then fibrous layer and so all those are working together to provide this synovial fluid Sac essentially that's filled with um this lubricating fluid and when a horse gets joint injections what they're essentially doing is going into this joint capsule and injecting a synthetic a synovial fluid to kind of help reduce friction and the movement of a joint is dependent upon the contraction of muscles and so the joints aren't just like moving around by themselves muscle contractions is what uh will make that joint articulate and move and then um we've got three different types of joints we've got cartilaginous joints fibrous joints and synovial joints so cartilaginous joints can move or not move um but an example of those would be between the different vertebrae on the horse um and so in between each vertebrae we have uh cartilage and um the little joint capsule we've got the snowbal fluid in between all the vertebrae um and some can move and some don't right we talked about the sacral part of that horse's vertebrae back here and how that's fused that doesn't move um but some parts oops I went to my other screen like up here in our our cervical vertebrae those joints can move right and then we have fibrous joints and so um as the matures those joints will harden into bone so they start off um as just a fibrous tissue at when the horse is a baby and then as the horse Grows Right think about as that horse grows a baby's skull a baby horse skull is not the same size as an adult horse skull so those joints were fused then um or are fused into bone then they wouldn't be able to keep growing so um they um stay as we think of a joint right as something that's kind of fluid and soft they stay like that until the horse is done growing and then it will harden into bone and then once it's harded into bone it's not movable anymore so examples of that would be in the horse's skull and you can see here like in the horse's mandible we've got some joints in here obviously there's parts of the horse's joints uh parts of the horse's skull that do move and articulate even when they're grown um but there are Parts in the H's mandible um that don't Harden until the horse is done maturing and then the last type of joint we have is a sovial joint and so our sovial joint is the one we think of when we think of a joint right it's freely movable um it's like in the horse's stifle or the horse's knee or their fetlock that's the joints we think of when we think of a a joint right we're not necessarily thinking about a fibrous joint in their skull so um so this image is pretty cool it shows um the stages of their skeletal development so what what age their spine or or their fet lock or whatever stops developing and it's fully mature so let's start with at Birth um at Birth their coffin bone um is developed and then at six month months their P1 P2 P3 bones um develop at one year their Cannon bones are developed at two years their carpus and Tarsus Nee and Hawks are developed now what are we noticing that the things closest to the ground developed first right and so as we move up this horse's leg that's those um growth plates are closing right their um upper long bones in their front legs and hind legs aren't developed till they're three um this bone here between their elbow and their shoulder isn't developed until they're three and a half and then we see their scapula and their femur bones um aren't fully developed until they're four their hip bones and their mandibles aren't developed until they're five and then at six years old is when their um the back half or or the coddle section of their thoracic vertebrae lumbar sacral and coddle are developed and the last to develop is C1 and then this cranial part of the thoracic vertebrae so that's just something to think about right when we think about starting horses or or training horses um being mindful of how we're training those horses because they're not their bones aren't fully formed and there's some people that think oh that means you shouldn't um ride those horses there's also lots of studies that show that actually working animals at a young age can improve bone density and um so strengthen their bones um you of course can overdo it yes but um there's two sides to every argument some people would say you shouldn't you shouldn't do anything hard with them until they're really old and other people and Studies have shown that actually if done properly it can actually be a benefit to the horse um they did not in horses but I remember in school learning about one research study where they took lambs and they did a research study they had like one group of lambs that they um didn't do anything with they had one group that they made them run every day just like across a little like 20 yards or something on like soft ground and then they had another group that they had run ac across like 20 yards that was like concrete and the ones that ran across concrete had way better bone density and way stronger bones than the ones that ran on soft ground and the ones that ran on soft ground had even better density than the ones that were just standing still in the pen so there's something to be said for working animals and trying to strengthen their bones but um this has just always been an interesting image to me so okay so let's talk about how many joints the horse has so their front legs have six joints the hind legs have seven so the front has shoulder elbow carpass SL knee fetlock past turn and coffin hind leg has the sacr iliac hip stifle Hawk and then the same fetlock passer and coffin so um let's look at the front legs first so this is a cool image that kind of shows us where these um bones lay in the horse and so um we've got up here we've got our shoulder joint right we got our scapula here our point of the shoulder and that's where our shoulder joint lies and then we've got our point of the elbow in our elbow joint um and so as we move down the horse's leg why am I spending most time talking about the lower part of the horse's leg H well this is a vet Med class and most horse injuries happen in the lower leg um they um if you look here this is a good image to show that um the higher up we are on the horse's leg oh my hand looks huge um look at how much muscle which also means blood vessels and all those kinds of things are surrounding these bones versus as we move down the leg there's less muscle which means there's less blood flow and so there's less protection for those bones and also if that if that bone gets injured there's less blood flow to these areas and so it's a harder injury to heal and so since this is a vetmed class and not a just a horse anatomy class um we'll spend most time looking at the lower parts of the horse's leg because that's where most issues will lie um so if we look at our knee here our carpus that's a hinge joint right so the knee moves back it doesn't Flex forward like this or extend forward excuse me um it hinges back and we've got tendons that will run on the front and back of the horse's leg to bring that limb either Flex it back or if the tendon's running on the front contract it will bring that leg back forward and then if we move down into our pastor or excuse me our fet lock so we've got that is what's attaching the cannon bone to this P1 our long past turn this is also a hinge joint so this joint moves back it can Flex back backwards or extend forward depending upon what um tendon is Contracting at the time and then as we move down into our P turn joint here we've got our P1 and P2 it's also a hinge joint and that will rotate back as well the coffin is also a joint um if the coffin rotates and flexes or rotates down that's an indication that a horse has a Founder issue we'll talk about that more later um but those are the joints we'll discuss mostly in this class so we've got the knee fetlock past turn and then down here we've got our coffin bone as well um it's highly likely on an exam I could give you a picture of a horse and tell and have you label um where the joints are or even we may even do that on a live horse and I'll have the horse Mark ABCDE e FG or whatever different joints and you've got to write on your paper fetlock Pastor you know coffin whatever so front leg is pretty simple the hind legs this is where kind of trip some people up I know there's a lot of words on this don't panic um let's start with the sacr iliac joint so that's just back here it attaches the um it attaches the ilium or the pelvis of the horse um to the sacral vertebrae right we talked about that already so we've got this little joint here and then we have our hip joint so that attaches the pelvis to the femur okay and so the horse's femur bone runs here we talked about that earlier and the femur um attaches to the tibia and fibia via the stifle joint so we hear a lot of people in the Performance Horse World say I got my horse's stifle injected and then I've had so many students that have gotten their hores stifle injected and they don't actually know where the stifle joint is on their horse so the stifle joint lies right here um and uh yeah that that's definitely a question that could be on a test I ask that question all the time because people don't really know where the stifle is on their horse but the stifle is right here um and again that attaches the femur to the tibia and fibia or fibula excuse me and then we've got the tibia bone running down and the hawk is what is going to uh connect essentially the tibia to the Canon bone and the hawk is a hinge joint the hawk will sweep forward like this and then as we go down the fetlock p and coffin joints are the same as the front legs um so there's all that so we've got Sacro iliac hip stifle Hawk fetlock Pastor coffin okay now let's look at a front view okay so let's start on the left and this is just kind of a good image to show um different arteries and veins the horse's windpipe you can see here the horse sternum I'm losing my voice even from like two days of teaching because I haven't talked this much all summer uh this has been kind of I've been like laughing at myself so if we're looking at the horse dead on front of them we see our scapula running down here and then we've got that shoulder joint right here facing us as we go down we've got that elbow joint and then we've got our carpass or knee right and then we've got our fetlock pter and coffin joint as we move down um so this is our Canon bone here right and we've got our scapula elbow this is just another way to look at this head on if we look at the horse from the hind view this does a better job if you can kind of see that sacr iliac joint here and now it's it's with the help of tendons and ligaments attaching um the pelvis to the sacral vertebrae and then we've got our hip joint that kind of Falls in here under this kind of the wings of the pelvis the hip joint is in there so we move down we've got our stifle joint our Hawk then our fetlock our past turn and our coffin bone as we move down so that's just an image here so the last thing we're going to look at and I've got to come out of this um PowerPoint sadly because this image won't move unless I am out of the Powerpoints this is a cool like 3D um image here so I just want us to kind of take a look mostly at the legs um of the horse so we can kind of get a better understanding of where Things Fall let's start with our front legs and just you guys can see here how that scapula actually comes up and over the rib cage and it it kind of the rib cage is kind of um underneath the scapula especially when you see it from the front you can see that scapula bone comes up here and is protecting the upper part of that rib cage and then underneath remember we talked about the sternum you can see that here um and just looking at like how much space that rib cage provides protection for those internal organs um and so moving back if we look here we've got our cervical part of our vertebrae right then we've got the thoracic with these spiny processes and then look here at our lumbar vertebrae how they've got processes that extend um laterally and so they've got this flat processes it it's almost like it it's always funny to look at to me because it looks like the ribs like forgot to curve down and we're just like flop we're going to be flat like this um but you can see that Lumber part of that vertebrae is very distinct and very different looking from the thoracic part of the vertebrae and then let's try to see a good image okay looking here remember we talked about our sacral vertebrae let me see if I can zoom in a bit looking here at our sacral vertebrae you can see that these are not get even closer yes here we go our sacral vertebrae are fused y'all can see that there's no gaps between them so the sacral part of this vertebrae is fused together and then as we move down the tail you'll see that coddle vertebrae they are not fused and that last little one is a little pointy okay so while we're here let's just look back at our might zoom out I've not used this 3D image before in a PowerPoint so it's a little I'm still getting the hang of looking at it okay so we see here that sacral iliac joint is what attaches it's kind of hard to see in here but it is right here right it's attaching the sacrum to the hip and so or to the pelvis so we've got our pelvis here and then our pelvis look at the back see the pelvis is quite a big irregularly shaped structure right it's got these Wings here it kind of comes down here but then it attaches here to our femur via the hip joint and then we've got our femur bone running down into our stifle and so remember on the front of that stifle bone we see that patella that kneecap we think of when we think of our own um body then if we run down here we've got our tibia and fibula you can see the fibula is that long thin bone and it is fused disly to our tibia and then we move down even further into our Hawk please hold there we go so we've got our Hawk here and then in our Hawk remember we've got things arranged in rows we've got our two rows here there other bones all in here I'm not going to ask you to know those um but we can see it's got this um this like dorsal process this top part that's sticking up here as we move down we've got our Canon bone here's our fetlock joint here let me zoom out a little bit so I can manipulate this a bit I need this little um maybe if I this is huge there we go okay I don't know if that's going to help me or not am I so here we have our yeah our fetlock this image isn't great we do have those like two little CMO bones remember we looked at those before um on the back of the fetlock and then here's our P1 our long P turn then we move further down we have our P2 our short past and lastly our coffin bone we've got a joint here in the fetlock we've got the pastor joint here and then the coffin joint here as well and so if we move to our front legs similar Vibe right um so let's just refer oh section of the image I wanted please hold so we've got our scapula humoris ol and so let's look here kind of see it scapula here right remember we just said that scapula kind of wraps around the top of that rib cage then we've got our humorous here going into our elbow joint this is our shoulder joint elbow joint and then we move further down we've got our Onna here and you can see the radius right here this like long thin bone moving down into our knee joint our knee our carpass also has a process it's kind of on the dorsal coddle aspect of our carpus bone and you can see those eight bones really well here so I got one two three four and then on the back side one two three four as well and if we move further down we have our Cannon bone fetlock Pastor coffin joint okay all right so hopefully that gave us some understanding of the different bones in the horse a question I could definitely ask would be you know the joints we laid out um let me do this the joints we laid out and these images right and then you should be able to identify just the bones I just went over kind of the big ones in the legs um and then you need to be able to identify let's go back to our spine yeah the sections of the spine so we got the cervical thoracic lumbar are sacral and coddle so that was a good overview of the hes skeletal system in some coming lectures we're going to talk about the horses muscle system as well as soft tissue so we'll look closer at the tendons and ligaments