Nora Grenager, VMD, DACVIM
11 minutes

Thank you, Dr. McLaughlin, for that lovely introduction. And let me just hide that. There we go. Okay. Hopefully everyone can see this well. Thanks for joining me today from all parts of North America and beyond. I really appreciate your time. As Dr. McLaughlin mentioned, I will pause in between sections for questions. So we'll just get started. Starting with an overview, just so you have a general sense. Don't worry, these are all relatively short sections. We'll talk a little bit about horses' unique anatomy and physiology and how those factors are useful to keep in mind when we're out working with them. Some stuff about equine behavior, and again, how that helps us sort of properly restrain these animals that are typically much, much larger than us.  A little bit about our kind of common history questions going through a basic physical exam and how to take the parameters of what's normal. I'll talk a bit about some routine things we do in terms of sampling medication administration, sort of routine preventive medicine stuff that it's good to have just the background on. Even if you don't intend on going into equine veterinary nursing, especially when you're taking the VTNE, these will be helpful things to have that background information on, including also a bit about some of the most common things we see horses for. Like, what are routine things? We all know about puppies with parvo or things like that, but what's our kind of common emergencies and exams in horses? And then I'll just have a final slide on kind of what life is like, you know, as I see it for equine technicians and just nice way to end up. 

Okay. So first, starting with some anatomy that's unique to horses. So the horse world itself has already evolved with a lot of terminology that is kind of different than what we use in other veterinary species, and so it's helpful to know some of those, because if you go out in the, you know, the client says things like, "well, you know, the left front ankle has been bothering the horse. And up at the croup, there's been some muscle tremors. And you know, Doc, I don't know. Ever since I've put that saddle, the withers have been weird." Just these funny words that we use in the horse world that sometimes still even catch me up this many years in.  So, I'll talk to some of those here in a second. And then to further that challenge, horses have some body parts that are really different than the other veterinary species that we work on commonly. So going through some of those interesting terms and body parts that are good to keep track of starting at the front and working our way back. Horses have these structures called guttural pouches. These are air-filled outpouchings of the auditory or eustachian tube, sort of the inner ear and you can't really see them from externally. Mostly we only visualize them with an endoscope or on x ray. And they're sites that can have infection, can have all sorts of other challenges. So we end up looking at the guttural pouches fairly often in horses. This image on the right side of the screen is looking through the scope, using the scope to look into a guttural pouch. That big white structure in the middle is a bone going through there, which is normal, called the stylohyoid bone. And then I've just highlighted a couple of masses that are in there called melanomas, but these are really unique to horses. Hippopotamus, I think, have guttural pouches as well, as do tapirs, which I only get to know because I got to help with a tapir once at the zoo because it was having a guttural pouch problem, and so they call the horse person, but things you wouldn't otherwise know. So guttural pouches are interesting and quite unique to horses. Also, I want to mention that in this talk I'll keep saying just horses most of the time, but really, I mean, horses, donkeys, mules, kind of all the equids that we typically see in veterinary medicine. But just for the sake of ease, I'll just stick with the term horse, unless it's something very specific otherwise. So, just past the guttural pouches, the pole is this region just caudal to the ears and people talk about that area a lot, especially in terms of musculoskeletal challenges. That's that first yellow arrow at the top there. So the pole is just caudal to the ears, kind of overlying the first cervical vertebra. Up next, we, I'm going to mention the withers. That's a kind of bony bump just at the back end caudal aspect of where the mane ends and just in front of where a saddle would normally sit. And it's comprised of the dorsal bony spinus processes of several of the first, kind of, handful of thoracic vertebra. And again, a common anatomical landmark to discuss. Now, the crest is this area i've circled that's kind of in-between the pole and the withers. And the crest is made up of primary, primarily ligament that kind of connects the withers and holds up those enormous heads that horses have, but it's also a spot where they tend to accumulate fat really easily. So you often hear people talk about like having, a horse having a really crusty neck, meaning like their crest is really kind of enlarged and sometimes wibble-wobbly or even kind of firm to the touch. 

Moving caudally still on the body, next up is the barrel, circled here, and that's really just like the body of the horse. So it's kind of the trunk and thorax and abdomen, kind of the main part of the horse. Flank is another term we use all the time, and that's sort of the region of the barrel that is behind the last rib and in front of the hip. So it's kind of that abdominal part of the barrel. Croup is another term that's used kind of for this musculature and region that over the lumbar and sacral vertebra kind of going out to the points of the hip and extending to the dock, which is the next term, which is another word for the tail head. So tail head and dock, same things. Moving on, another kind of bony protuberance, people often talk about, especially when I'm talking about where something is located, like in relation to this point of the hip or when they're talking about things like how a horse moves, the point of the hip is a bony protuberance called the tuber coxae, part of the pelvis. And kind of the bony bit that sticks furthest out when you're looking at the horse from behind. And then finally in male horses, they have a sheath, which I'm going to show you an image of here, which is kind of this telescoping skin that covers the penis. So their penis is usually retracted. It's retracted up in the sheath, and then when they are going to urinate or reproduce, the penis will drop out of that sheath, and the skin just kind of flattens away. This one is a bit swollen, but it was good for purposes of demonstration. And sheath cleaning is something, veterinary and veterinarians and veterinary staff end up doing frequently for people because horses don't particularly enjoy having that area clean. 

Okay. Moving on to the limbs a little more. On the hind limbs, the top joint that we often talk about is what's called the stifle, and that's what we would call a knee on ourselves. So it's sort of the femopatellar, femorotibial joint, and we never call it the knee in horses. And I'll explain why on the next slide. You'll see that. But so we call that the stifle. The next major joint down is the hock, also known as the Tarsus. And so that's just that joint in the hind limb that's specific to the hind limb as well. Up next is this Canon region. And so officially that's called here on the hind limb it's called the metatarsal region. But the exact same part exists on the forelimb just below the carpus and it's called there the metacarpal region. And so that area has lots of soft tissue structures going through it that like bone tendons and lots of abnormalities can happen in that region. So Canon's a good term to know. Moving to the lower limb a little bit more, the fetlock is this joint which is often unfortunately incorrectly called the ankle. So that's very commonly termed as the ankle, even though it's very different from our ankle. And the official term for it in the hind limb would be the metatarsophalangeal joints. So the joint between the metatarsis, that canon region and the phalynx, or the digits. And in the front limbs, the metacarpophalangeal joint. And then the pastern is the joint just below that, and it's either the proximal interphalangeal joints, so the first joint of the distal digits there, or it's just kind of that whole region, that little that little space that's highlighted in the image there between the fetlock and the hoof, that there is called the pastern region. Moving further down the limb even, the coronary band or the coronet is where the skin, the haired skin ends and the hoof starts. And it's really important tissue, actually, because that's where the horn of the hoof is actually produced. So if there's an injury there of some sort, especially like a laceration and it's not put together properly, that little area isn't able to make hoof tissue. And so there will be a defect in the hoof wall at that spot. The joint just below that, the very final joint of the limb is the coffin joint, also known as the distal interphalangeal joint. And it's called that because that third phalanx, so the distal phalanx, the last bit of bone in the foot there lies inside the hoof capsule, kind of like a bone in a little coffin. And that's how it got its name. So it's the coffin bone and the coffin joint, and again, an area of a lot of musculoskeletal evaluation in that region. Just behind that, palmar or plantar to it, is the navicular bone, which is very small, about this big, little sesmoid bone that allows the tendon that deep digital flexor tendon to slide over the the back of the heel there. And it's an area that's commonly responsible for, or commonly vindicated, for lameness issues. And I have another image of it here just to kind of show it even better. So this is a limb of a deceased horse, obviously, that's been dissected and the navicular bone is this tiny little guy here, which the orange circles around. But it's a source of a lot of challenge. So good good one to know about. We all know what the hoof is and hoof wall is kind of obviously the main part of the hoof we see. And then the whole bottom surface is called the sole. Of the sole, there's this special little area called the frog that looks like that. This has been recently trimmed by the farrier, so it looks like especially cleaned up. But the frog is found that V-shaped structure in the sole. And then the last kind of limb terminology I want to mention is the knee. And this is why we don't call the stifle the knee and the hind leg, because long ago they started to call this joint, the carpus, the knee. Anatomically, completely incorrect, but still very commonly used term.