Hi, welcome to, the webinar, for Avian anatomy. I'm gonna, my name is Andrew Cushing. I'm a vet at the University of Tennessee, graduated from Liverpool in 2007, and we've been doing primarily zoo practise, since then, but with some birds thrown in as well.
And this is a lecture derived from, vet students that we give to vet students here. Of avian anatomy, primarily, but I've tried to make it so it's pretty clinical, rather than just lists of muscles and bones. So, hopefully it relates to clinical practise or birds you may see in, in your, practise.
So I think understanding some of their anatomy is really important to be able to treat and manage conditions, you know, knowing what's normal to know what is abnormal is really a big . The main facet, I think. So we'll go over some topographical stuff, so what the feathers, skin, feet and beak should look like, and then we'll move internally, and as I said, we'll relate this to diseases or conditions you may see in practise or even just routine care.
So obviously, they have some fairly unique adaptations primarily for flight is the first one that springs to mind, and that is, a combination of the feathers, the musculoskeletal system, and the respiratory system all combined to provide them with that capability for flight. There's some funny adaptations, for digestion, so going from the beak and then through the GI tract as well. It's pretty thin skin, which is derived into beaks, claws and feathers.
This is the side view of an owl and this is actually his ear, so in an open ear canal and you can actually see the back of the eye from here. So if you, if actually you can . Take owl's eyes out through the ear is actually the recommended way certainly for large owls, but this is should be part of your physical exam to visualise the ear, and people see this hole in the head and kind of surprised by it.
It's hidden away and then all of a sudden you're parting feathers and you see this huge gaping hole into the skull, which is kind of a funny thing. This is just a picture of a budgie just giving some general terms that you can probably guess for most of them. There's some new words in here, so is this bit, you know, just above the, the beak, the rest of it is probably pretty .
You know, basic stuff, the cloaca or the vent is the exit hole which is down here. So you may see budgies, they're fairly common. You can sex them, you can sex budgies, so males have got a blue sear, females have generally got a pale brown or a paler slu for boys, makes it pretty easy to sex a budgie if someone brings one in and wants to know if it's a boy or a girl.
And these are eclectus parrots. These are the most sexually dimorphic, so redder females and greener males. Aside from that, outside those two species, it can be fairly difficult to sex them.
You know, a lack of sexual dimorphism, and DNA sexing is really the only way to go about it. I think looking at the external anatomy gives an opportunity to connect to the owners. You can, you know, comment on the condition of the feathers or the condition of the body, feet, you know, anything, and just to kind of connect to them, even if you're not an avian vet, every day, I think, you know, that gives you a kind of in with the owner.
Some feathers, you know, I believe this is not, this is more academic than anything, but, obviously the functions for the feathers include flight, thermoregulation, buoyancy for water species, courtship if you're a bird of paradise over here, for UV protection also for camouflage. So a range of functions that they perform. And they, they're made up, like kind of microscopically, that the shaft is called the raki, and that's the main shaft that you would use if you were using a quill pen.
The calamus is the part of the raki that sits within the follicle, and that's, you know, this end piece without any, any barbs or barbules on. Barbs arise from there, and there's barbules that interlock with the barbs here. So that's why when you, when you find a bird feather on the floor and you kind of mess with it, it all kind of sticks together, you know, when you, when you run your fingers down here, because all those barbules hold all the barbs together.
The flight feathers are probably the most important feathers, I'd say, and certainly for the mechanism of flight, and they are primary and secondary. So this is the, the wing pulled out from this bird. The primaries are numbered 10 to 1 and the secondaries are 1, about 1 to 12.
It varies a little bit with species, but usually, you know, that's the, that's the number of them. And these are important because, you know, looking at feather condition is important. So you know, when a bird comes in for a physical exam, it's important to know again what is normal and what is not normal.
So here, this circle, this blue part, this is a blood feather, so this is an actively growing feather. This will bleed a lot and it will hurt if you cut it or break it. So don't do that.
It's a fairly common presentation for people to bring pet parrots in that are, that are bleeding, they can't find a a wound, it's normally a broken blood feather, and, you know, cautery either with the powder, or . Like a cory pen to stop it bleeding if it's still active is is generally pretty useful. Broken feathers, so this is a bird that's placed up in a chimney or in a box or something, so he isn't broken feathers.
They will moult out over time and new ones will grow through, which will look like this. And then these are what we call stress bars. So this is an animal that's had some disease process in previous history, and during that time, the feathers develop defects as they grow.
So these are stress bars, so you can use that as an indicator of previous, issues. When you're trimming, feathers, just to go back, people will often ask you to trim their bird wings, can't fly. There's 2, there's 2 trims.
We normally just do the primaries and you cut them here at the level of the coverts. So cut them across here. Try and separate them out one by one to make sure you don't cut any blood feathers.
And there's a complete trim, which is kind of 10 to 1 through the primaries, and that will mean they don't fly. There's a show trim, which is where you leave the first two feathers and take the rest, and what that results in when the bird is perched and the wing is across its back. It's, it's difficult to tell that that bird has actually had.
Feathers trimmed on its wings because these first two primaries kind of cover up the rest of the wing, if you will. So that's what we call a show trim. What I usually advise to people after a feather trim is when they take the bird home, don't just let it loose, try and let it loose over a mattress or a sofa or something soft because nobody told the bird that it can no longer fly.
And we, we would see a lot of injuries where birds would have their wings trimmed and they'd go home and throw the bird away and he'd jump off or she would jump off the cage and just crash to the floor and hurt themselves. So for that first. Release, do it over something soft, and give him like a mattress or a sofa.
Skin we mentioned is fairly thin, so we've all seen chicken skin before, and this is a duck that's got sutured up here. Usually 3 or 4 out suture is the way to go. Use a tapered needle.
If you use a cutter needle to triangle on it kind of tears through as you suture it, it's kind of too traumatic. Very liable to tear just generally, so I think be, be cautious when you're suturing that, when you're doing surgery. On the face of this macaw, this is a, this green spot here.
This is something we see fairly commonly and owners will complain about it. This is a bruise, and what happens is when you're, when you're holding the bird, you generally hold it here because you don't want to get nailed by one of these. They will bruise green because they don't, they lack the enzyme Billy bird in reductase, so they'll they'll bruise this kind of dark green coloration.
And owners will often ask why he's got a green splodge on his head. It doesn't seem to be painful. They don't seem to react to it post handling, it just seems to be there and it resolves in a week or two.
For the feet, they usually have 4 digits, so it's 123 and 4. So this is a bird with digit 1, which is the hallux, which is on the points backwards, and then 23 and 4, counting that way. And they have these pads which are used for cushioning underneath, and that's where you get things like pota dermatitis or bumblefoot, whichever you will, and developing on birds here, so always look at the base of the feet, it's certainly useful and you can pick up health defects there.
Two, there's a few main, there's a few foot types, but there's two main ones. So anisodactyl birds and zygodactyl. Anissodactyl are birds that perch.
So things like raptors, they have the halos, as we said, digit one that points backwards here. So this is a nisodactyl bird and the zygodactyl. These are climbing birds or birds that use their feet to kind of help them eat.
So these are parrots, basically. And you see they've got 2 pointing backwards and two pointing forwards, and they use their foot like a hand almost. And again, know it's normal to know what's abnormal, so this is a normal d foot, some normal chicken feet with big spurs on.
And so you can see what's abnormal. So this is, this is a low grade bumblefoot in probably a cockatiel or something. So you can see the pink kind of hot, warm lesions there that you would expect.
Often we see this if birds have got poor perching material or they're overweight or they have disease on the other leg and they bear too much weight on, on the contralateral limb. This is obviously a, a duck, webbed foot that's been torn. This is a budgie's foot, and you can see the lesions here.
So there's little swellings at the joints. Here is probably the most distinctive. And this is actually, articular gout.
So, looking out for that in certainly older animals or animals that have been, had, maybe had some previous insult, it's certainly worthwhile to look out for gout lesions. People will bring the birds in foot care, so it's basically, nail trims, and a few different ways to do it. So be careful with the quick, especially in something like a raptor's foot when it's black, you can't see it.
I always imagine it goes through 90 degrees, so if you imagine the toe comes here, you can see my arrow, it comes through 90 degrees and the quick ends about there. That's approximate. And you can see you can take it from here to here.
Now you can do it two ways, either with a Dremel, which is slower, but you can be a little bit more cautious with it. It just gradually works the nail backwards. If our, or there's a culture pens, so these battery powered culture pens actually work pretty well.
So you get this, you hold this button down, this, this big it's really hot. You can put the nail in and just draggily drag the nail through like nice and slow, and it'll melt it as it goes through and actually take the nail off nice and cleanly, and we'll cauterise it at the same time. This is faster, for certain birds that don't want to be handled, they're pretty stressed.
It can be problematic to hold them for a dremel because it takes longer, as I said. So this is a faster way to do it. The beak is also made of keratin and it has a continuous growth.
The top is called the rhinotheca, the bottom is called the natheca. And just to show you kind of what it looks like, you can see where the bone extends to. So this is the premaxillary bone here, and that you can make out, the, the keratin from the rhinotheca extending beyond that.
So that's important to know if a bird comes in for a trim. So imagine the bone is probably to about here. Maybe a little bit less.
It's obviously impossible to see it unless you take a radiograph and put marks on. So be careful when you're trimming these beaks, and you kind of take it back a little bit at a time and take it nice and slow. You can open the mouth and do the base of the bottom beak as well, and reshape it.
So here's some beakca pictures, cockatiel just for the dremel, just getting a beak trimmed and again here this is, we call it coping when we do raptors. So this is a bald eagle getting his beak coped. Into a nice shape, it's too long.
Don't hold it on for too long and beware of thermal necrosis. There is a couple of reports of budgies that have had germals, used on their beak, and they've had brain necrosis from thermal because it's got too hot. So be careful of that, that is definitely a bad side effect.
And then you may see beak abnormalities. So this is what a normal beak should look like for a parrot. You can get scissor beak, you can get overgrown top beak, overgrown bottom beak.
And these are obviously pretty severe examples. So this, this bird here, usually we see this if they're with another bird or they stick the beak somewhere it shouldn't, and then, and their companion kind of bites it off. And this is obviously a problem.
They can't eat crunched nuts or seeds or anything like that from this point, but they're pretty adept with their tongue, and they can adapt fairly well, but obviously that's a medical management and maybe this is never going to be back to normal again. This one on the right, this grey parrot with a scissor beak is obviously a severe example of some of some beak beak abnormalities. And I think the thing to do is do this step by step, do it pretty slow.
Don't, don't expect that this is going to be back perfect with one trim, I think. Do, do some, see how the bird handles it, you know, do some more in a couple of weeks and gradually bring it back to normal. And it gives the bird a chance to adapt to new beak shapes as, as it becomes normal again, which is certainly helpful for appetite.
Moving into the inside the body into the skeletal anatomy, so they have this large bony orbit, which the eyeball was completely fills. They have bones around the back of the eye called sclerolosicles, which strengthen and support the eyeball, and the iris actually has striated or skeletal muscle. So it means if you need to dilate a bird's eye to look in the back of it, you can't use atropine because that that only works on smooth muscle, so you have to use rock uranium or .
Rocky Road is a skeletal muscle blocker, so you can use that fairly successfully to dilate bird eyes. So atropine's not going to be helpful. The skeleton as a whole is really adaptive for flight, so it's pretty lightweight, but it's also strong.
So if you imagine a bird crashing down out of the air to land on a mouse, it's got to have some strength to it. It can't just be very brittle. So it does that in a number of ways, .
It has birds have got a lot of cervical vertebrate, it ranges by species. It means the neck has a lot of flexibility and the body can stay and the spine can stay relatively stable. So the neck is really the movable part of the bird as we see this owl is adeptly showing us here.
They have pneumatized bones to add to create kind of lightweight situations. They connect to the respiratory system, which is important to think about if you're well we'll come on to it in a minute. And the humerus and the femur and some vertebrae are classically pneumatized bones with some species variability.
Avoid putting fluids into the humerus and femur, I think is the take home point, because with the connection to the respiratory system, potentially you drown these animals. For support, they have trabecula, so you can see this kind of mesh web network of trabeculae within this bone here, and that kind of gives them support without adding too much to the weight. So again that's a flight adaptation.
And here's why we worry about pneumatized bones. So this is an intraosseous catheter. In my experience, intraosseous catheters are way more useful in birds than intravenous.
The intravenous catheters fall out, they pull them out. If you get them in the neck, you know, it's just too movable. You can get them in the leg and it's a problem.
The wing is so superficial, the wing vein. So really, I turn to IOs in the ulna primarily, and that's what's happening here. And it's probably beyond the scope of this for exact like methods of placement, but you can certainly find that online for tips and tricks on how to place them.
But this is a position you would, you would kind of hold it in and I overlaid some bone pictures here just to show you kind of where you're driving down to get that catheter into the ulnar. And certainly RAD's post placement is helpful to prove that you're in there. So back to the strength of skeletons, we see this bone fusion.
So the tarsus and the metastasis is fused to form the lower bones of the foot, it becomes the tarso mettatasis. And the tibiot Tarsus, which is the tibia and the upper bones of the foot, the pigger style is the few remaining caudal vertebrae, kind of fused as one. Then they have a pelvic girdle, which is, or the syn sacrum, which includes all the lumbar vertebrae, the issue, the ileum pubis, and some of the caudal vertebrae fused in this huge kind of box which is called the syn sacrum.
So you can see they have the same kind of bony structure, but that bony fusion means they're not sacrificing. Strength to, to provide a lightweight skeleton. The spinal column has got blocks that are fused, so that's why the neck, provides most of the flexibility because the actual rest of the spine is relatively immobile.
They have fercula, which is two clavicles, so the two clavicles are fused to form the fercula. And they have these unsyate processes on the ribs, so the ribs have these braces on and what happens, that's kind of a shock absorber, if you will, you know, if the bird has trauma or lands on the ground fairly solidly, these, these ribs brace against each other to form a network of a bracing system. Very prominent keel, so it's not flat like our sternum, so it's this keeled sternum which sticks out there.
And this is where the large pectoral flight muscles attached to. So this is where you'll carve your roast chicken from, you know, either side of the keel. If you get lost, just think about it compared to an arm, so I thought this picture was kind of cool.
So it just puts it together to show you exactly kind of where the bird bones kind of fit. You know, if you get lost, you can relate it back this way. The wing, has an alula, which is this first digit here.
This is also called the bastard wing, a major and a minor metacarpal. The major is bigger than the minor, obviously. Remember, the pneumatized humerus.
It's got radius ulna, same as us. And that's, that's what the wing looks like. So this is the manners.
This is essentially what the hand would be. And as I said, alula is digit one. The pectoral girdle is vitally important for flight.
This is a meshwork of bones that includes the coracoid, the scapula, and the clavicle, and that forms the triosseous canal. And the supraoricodius muscle is essentially one of the big flight muscles, one of the two big flight muscles. That uses this trioous canal, and I'll show you how in the next slide.
But this is what they, this is like the front view of the bird. So the fircula, which is the caricoids, the clavicles, sorry, the caricoids are behind that. The caricoids here, and the scapular points backwards along the rib cage, and this forms the triosseous canal.
So here you can see this is the supracaocodius muscle kind of filtered on top of the bones. So here we've got the, the bones again. Supracariodius comes through the triosis canal through this hole here, formed by these three bones and attaches to the humerus.
So it means when this muscle flexes, the humerus lifts. So this is how a bird manages to raise and lower its wing without any real major musculature on its back. It's all ventral.
If you think about, you know, how you would expect it normally, it's a lot of back muscles would lift it and chest muscles would pull it down. In birds, it's ventral muscles that lift it and pull it down. So here's where most of the muscle mass is, pectoral muscles here, you know, when you roast chicken as you keel down the middle, supraoricodius is in there along with the pectoralis muscle, and the pectoralis muscle attaches ventrally to the humerus and pulls it down.
The supraoricodius attaches dorsally through the triosis canal and pulls it up. So what that means is that birds that have trauma, so particularly wild birds or raptors, you know, they fly into a window or hit a car, if they present with a dropped wing, which is a fairly common presentation, often there's damage to that triosius canal. What, what, what it means is the bird can no longer elevate that wing, because this is kind of broken down.
There's another diagram for you to show, to kind of demonstrate this, the supraorricodius comes up here through the Triocese canal onto the humerus and pulls it up. Pectoralis comes here and pulls the humerus down. So here we see a drop shoulder or a drop wing, as a, as a pretty common sequalla of trauma.
The propetagium is B, which is this band of skin here, so this is the shoulder of the bird and the body, just to orientate you. Coming down here, this is the elbow C and the end of the wing is over here, just off off picture to the left. And what happens, this, this can flex this can extend and flex with the wing as it extends and kind of folds into the body.
The ulnar vein C is here, so ulna or basilicate vein, you can use for blood collection, that's a fairly superficial vein and nice to hit. Trouble with the propetagium is if you have to put a bandage on a bed, you should release it at least, at least every 2 days and probably more frequently than that. This propetaal ligament, which is B, can actually fuse or shrink and contract, and that can end up resulting in a permanently debilitated birth that will not be able to flex to fully extend its wing.
I guess there are questions in there, but as we're not live, I guess, send any questions later. Before we go to the GI tract, so very simplistic view, but just to take you through it, there's oesophagus, go into the crop, which is a different thing to mammals. Then the stomach is made up of the proventriculus, the gizzard, and then the intestines, sika and oica, which is the exit hole.
It's a little bit of a more real diagram of the GI tract, if you will, rather than a cartoon version. So just to take you through the oral cavity, we mentioned the beak, but obviously that's the start of it. They don't have a soft palate, so this is all hard palate.
And these papillae, you want this kind of shaped papillae. Vitamin A deficiency is something we see in parrots for, you know, a seed diet, I think, would be the main . The main causative factor of vitamin A deficiency, and they'll get blunted papillae, so look out for that.
And the oral and pharyngeal cavities form the oropharynx in birds. So this is the ka, it's the gap, and it has papillae which kind of is supposed to stop stuff going up there. The tongue has this laryngeal mound here where the glottis is.
So intubation is relatively simple, you know, it looks really easy here, you know, you just drive it down there. It's helpful if somebody pushes a finger underneath the chin. There's a soft part, you know, below behind the lower beak, which you can push forward.
That raises this mound and makes the makes the glottis very apparent and easy to intubate. After oesophagus, we have the crop. This is basically a food storage chamber.
It's really a diverticulum. And what this is for is for, you know, prey birds like pigeons. They don't want to hang around on the floor for 3 hours and eat a load of food.
They want to get there, get the food and fly away somewhere safe, so they'll fill the crop up and fly away, and digest it later. So it's a food storage chamber with some food softening, I guess. It's pretty close to the skin, and pigeons is a prime example of a ruptured crop.
You know, they, they fly away with this huge bulging crop full of corn, and traumatise it. It often ruptures and, and you can see food coming out onto the outside of the skin. A relatively easy fix, heals well, just suturing a couple of layers and suture the skin closed.
The other, the other time clinically we see issues with the crop, primarily is if people are hand raising parrots and they use formula which is too hot, and what'll happen is it'll burn through the crop and you'll see it come out through the skin. And again, that's just a dissection, you know, take away necrotic tissue and close it back up again. And those are really the issues we see with the crop.
After that, you get the proventriculus, which is this area here. You see on the radiograph these small arrows indicate the proventriculous, and this is kind of the glandular stomach. After that, you get the gizzard, which is the muscular portion, and this is a twisting, churning part of the GI tract that where the muscles will crush seeds or anything like that.
Birds will often eat rocks and stones, and you'll see them in the gizzards. So if you see this pre oops, if you see this previous radiograph. Where is it?
Here, this is the gizzard. You can see opacities in there which is consistent with usually rocks. And this is a parrot, radiograph and is eaten just a few rocks, which is fine.
It sits in the gizzard and it helps with the, the crushing digestion. You will see skeletons in here if it's a raptor and seeing a mouse or a snake or something. So here's some more.
So here's a gizzard with a few in, but here's a gizzard with a definitive number of them of rocks and stones in there and that's perfectly normal. He's an eggs sticking to this one too. After that is the cloaca.
There's 3 sections, the coprodium, the uridium, and the proctoiumium. Basically this is the reproductive, the ureters for urine, and the faeces mixing chamber before it comes out. So this is where it sits in this whole chamber before it comes out as waste.
The liver does nothing different in birds than mammals, so I'm not gonna go into a huge amount other than its location. They don't have birds don't have a diaphragm, so there's no separation here between thoracic and abdominal cavity, it's just a silomic cavity. And the liver just kind of sits there and surrounds the heart.
The spleen is pretty nice to see a radiographs. You can generally see a round ball there, and that's a good good identifier for infectious disease. A lot of infectious diseases will come up with splenomegaly.
More than twice the thickness of the femur is the rule of thumb, but it's not, certainly not a given. But that's, a kind of nice idea to see if you've got obvious splenomegaly on radiographs. Shape can be a little variable, but generally you'll look for it on an X-ray this way.
The urinary system, they have kidneys and ureters, which is great, they don't have a bladder. They do produce urine, but it's uric acid rather than urea. So whereas mammals, you know, dogs, cats, us will produce urea and a pee, reptiles and birds will produce uric acid, and that is because, as they develop within the egg, you want the least toxic.
A nitrogenous waste product, which is uric acid. Clinically it's important because if you blood sample a bird, BUN means nothing. You want to look for uric acid.
That's the, that's an indicator of renal function. And so look for uric acid when you're doing that on a on a bird chemistry. And here's a urate, which is the white, the browny green stuff is faeces, and then the pale is urine.
So this is a normal bird dropping. And I think, you know, it's important to know what normal is. So here's a normal urates, faeces and urine dropping.
You know, here we can see what some abnormal things are. So, coloured fruits or vegetables can cause issues. I've certainly had people come to me and say, why have my birds pooped red?
Because you fed it raspberries yesterday, and it's normal and goes away. But you can have diarrhoea, so this can all mix up and be diarrhoea. There's, there's a lot of kind of anecdotal stuff that green discoloured urates indicates liver disease, and certainly we've kind of ran with that.
Avian vets, I think, and always, you know, do our due diligence and check for liver disease. I'm not totally sure if that pathogenesis is fully understood, and it's certainly not pathodemonic, but if you see that, it's worth, it's probably worth looking at. You can see blood, you can see in digested food, which may indicate certain specific diseases.
Or if they have enteritis, so clostridial enteritis, you will see bubbles through the, through the faeces as well as, as that's that's like gas producing bacteria comes out. So the kidneys live up here, so it's right in the sin sacrum if you remember this pelvic box pelvic bone. It's called the sin sacrum and the kidneys kind of really hide up there.
3 lobes. They go, they, they hide in the bones so you can't see them radiographically. That's the, that's the hard bit.
If you're seeing them, you're probably seeing . Either testicles or ovaries which kind of sit, or adrenal gland which sits on the front end, or if they've got renomegaly, potentially you might see them peeking out that sins straight up on a radiograph, but they're pretty hard to pick up radiographically. The renal portal system is something they have, I don't know if you've heard of this before, but this is something that people ask me a lot, you know, can you give injections in the back leg of a bird or a reptile, because they have a renal portal system, which means that kidneys have dual afferent blood supply.
So the external iliac, and the sciatic veins, and the sciatic veins come from the legs. The answer is, I don't worry about it too much. I think .
It's not a huge concern of mine, but generally we don't inject birds in the legs anyway, so it becomes even less of a concern. This is a pretty common presentation to see a lame budgie. You know, it's kind of got a flaccid paralysis, if you will, of a leg, and this is commonly neoplasia, commonly renal adenocarcinoma, which they are prone to.
You can see here these red arrows pointing out to the kidney, which is way bigger than it should be, and this is because there's a tumour in there and the sciatic nerve actually passes through the kidney. And so any kind of renal disease or compression, certainly with renomegaly or neoplasia can cause an issue. Got this in, so questions, just what we've been through so far.
So we've been through all these in bold, so respiratory and circulatory to go. The respiratory system, everyone knows that people send canaries on the coal mines because they're highly efficient at the the the respiratory system is highly efficient. In comparison to mammals, they don't have a diaphragm.
They have air sacs. They vocalise by the syrinx rather than the larynx. They have non-expandable lungs, and they have pneumatisation of bones.
So quite a few differences, which we'll talk about a little bit clinically, in the in the next couple of slides, but basically, highly efficient respiratory system. So here's a bird with a running flower in its mouth, but you can see you can intubate in here, there's the windpipe coming down, these are the lungs kind of hiding in here. So non expandable, not like ours.
The windpipe has got complete complete cartilaginous rings, so we don't recommend inflation of an ET tube cuff in case you cause damage. Just choose a a cook tube that's not, that's not inflatable, that's a good fit. And your bird respiration, one inhalation, it's unilateral, so as opposed to our lungs.
When, where we breathe in and we breathe out through the same breath. In the same lung, it's bidirectional, this is unidirectional, so we inhale here. As you exhale, just taking that first breath.
That then moves through, through the, through the lungs, which is this mesh system here. Then the next inhalation pushes it back into this air sac, and the next exhalation is that first breath going through. So, in, out, in and then out before that first kind of pocket of air leaves, if you will.
So they have these air sacs which act as bellows, usually 9 of them. And it means that, . Oxygen exchange is during both inspiration and expiration, which is why they're so efficient.
And helps with. Certainly gaseous anaesthesia. And it also aids to cool the bird as well.
So, here's a, a diagram of it. You can see we're going into the, into the humerus here. It's not showing the femur, but you can see the air sacs, the caudal and cranial air sacs in that bird.
This is worth a review, if you want. I'll leave it on here so you can copy that website down. This is, a bird that, a video that goes through the respiratory cycle of birds and shows that you in kind of a graphic format, which is worth, worth a watch if you have a few minutes.
They have nucleated red cells. They have a 4 chambered heart, which is fine, that's exactly the same as a mammal heart really. The nucleated erythrocytes will mess you up on a blood count in a normal machine because the nucleated reds counts counted as whites commonly.
The heart, we mentioned no diaphragm, it kind of sits here just in front of the liver, and it's surrounded by the liver lobes at the apex. The blood sample birds, which is obviously something people want. This is a jugular, so this is the right jugular vein, which is much larger than the left.
And they have this handy featherless tract. Most species have this. It's called an aptera.
And if you hold the bird, depending on the protocol, we use to sedate all birds to do this or anaesthetize them, . I think there's probably no need to do that if you, if you're fairly quick with it. But you can have someone to hold, kind of wrap the neck around the finger and open up this Aptera here, which is a featherless area.
Very superficial, the jugular, but it flows fairly nicely, so if you get it, you can get a sample fairly easily. This is the basilic vein, so it comes through here over the elbow. So this is the bird lying on its back with its wing out.
This is very prone to. Hematomas. So my recommendation here is, as you, as you put your needle into the vein, which is so superficial, you know, it's through like, you know, less than 1 millimetre of skin for sure.
Keep negative pressure kind of as you advance, and that will reduce the chance of that vein blowing as soon as your needle goes into it. That's the, that's the main issue with this vein and then hold it, hold a cotton wool after it, over it for a while afterwards. And then there's the metatarsal vein, which is the medial metatarsal vein.
This is a, a goose probably, I think. And so this is the back of the leg, the front of the leg. There's a groove there and there's a vein that sits right over it there.
You can see it down here and you can see it up by the tarsome meatosis up here. But actually if you go in anywhere in that groove, you'll be able to hit a vessel fairly easily. So a couple of resources for you.
Surgical anatomy book is handy, and shows you approaches for how to get to it, how to get to each area, which muscles to go through, which bones to get through. That's the handybook. If you want more avian anatomy, I borrowed a lot of pictures from this book, which is the McClellan book.
This is 3D bid Anatomy, which is a, a computer programme, you pay like, I don't know, 10 pounds or something for the licence for a year, or for life maybe. And it gives you 3D bird anatomy so you can play around with it, so you can take bits on and off so skin, muscles, skeleton, spin it around, take things off, add things in, you know, see where things look in relation to a bird, which is kind of handy. So that's what we went through in this.
If there's any final questions, I guess let me know. Other than that, I hope that was helpful and somewhat clinical.
