[Music] hello everyone i'm going to be doing a postmortem otherwise known as the necropsy as a demonstration today the purpose of this video is for our students our vietnamese students to see what a dolphin postmortem is like i'm going to use our specimen today is called a common dolphin scientific name dolphines delfinai and this is a dolphin that has been stranded along our coast in the western cape and it's been donated for us to use today so i'll be going through the process with you step by step and be giving you a little bit of information as i go along on the organs to start off with i just want to show you what we need um to be able to do a dolphin bus motor firstly you need a clipboard and your data sheet to record everything next you need formula this is ten percent formula to be able to sample for histopathology we also need alcohol this is 80 alcohol and that's for the parasites if we find any internal external parasites and then we need sample bottles for bacterial and fungal culture samples and these are sterile sample bottles next we need our instruments to cut with so we have rib cutters if the animal is large you will need that you we also have smaller ones for smaller animal we need measuring instruments so we have a ruler and we also have a longer tape measure and importantly we need a sharp knife we also have some scalpel blades if we need to do small dissection and some rope which we'll use to tie off the intestine as we take it out so that we don't have any spillage important to have a permanent marker so that your samples are marked correctly and we also have some bags if we want to take some fresh samples with some paper to mark that with okay before you start you'd also needs to be defrosted so um often dolphins are frozen when they've been found beached and they need to be defrosted properly before one does the post-mortem the best way to do this is to keep them inside in a cool area not in the sun because that makes them utilize much faster so before starting to open the animal we're going to first check that the whether there are any signs or trauma or anything that can give us an idea of why the animal has died so we're going to do an external assessment you can see that there are some marks on this animal there are some scratches here and there are also some scraps here on the dorsal side these are important for example if you are worried about boat strike you often find that parts of the flippers might be missing so it's important to make a note of that on your data sheet what we also will check externally is whether it's a male or female we do that by looking at the distance between the genital slit and the anus in males they are longer than 10 centimeters between the two you can see this is 13 centimeters so this is a male females the genital slits and the anus are closer less than 10 centimeters in addition females will have a mammary slit on either side of the genital slit of ear males can sometimes have that so one just has to check very carefully and use that in addition to the distance between the two openings if you find it often or if you're called out to do a dolphin postmortem it's important to take some morphometric measurements these help researchers to determine the types of animals the ages and also the gender um that's being stranded so one of the important ones we'll take is um from the tsukusha nose and it goes all the way down to the cleft ear between the flukes the other important ones are find where the animal is at its broadest and you take a girth measurement so it's full around the body a circumference and then also um along the back end of the animal and then also right in front of where the flippers are so those are the basic ones there are more we will have them available in the reference that will be at the end of this video and you can then get it from those data sheets so we're going to start by taking some samples of the skin and the blubber it's important to check the thickness of the blubber because that gives us a good indication of the health status of the animal we will take samples from right cranial to the fin in the same line in the middle of the body and then in the same line ventral in addition to that we will take one right down below the tip of the fin so those are the four samples we'll take and we will record the thickness of the blubber [Music] there [Music] so they have taken out the first bit and what we'll measure is the blabber thickness which will be just under where the skin ends down to where you start seeing the rear tissue of the muscle so in this case the most dorsal is six millimeters at the midline it's 10 millimeters and down eventually it's also 10 millimeters [Music] and where we have the sample that's right under the fin and that measurement is also 10 millimeters let's take some samples of the blubber that we've just removed so 10 percent formula as i mentioned earlier and remember with formalin you want to have a sample that's not thicker than two centimeters otherwise it doesn't fix properly so we will take a sample of all three areas which will be ventral dorsal and mid body area and that's about the size that i'm going to take and that goes into the formula for fixing and for histopathology next i'm going to remove the rest of the skin along the body wall so i'll start by loosening the flipper and the shoulder and that's the scapula or the shoulder attached there to the front limb in effect and then for the skin incisions we are going to go along the dorsal area and basically meet up with these lines that we've already made for the for the previous skin samples and down the length of the body and then also meet up with the ones eventually and then where we've removed the the shoulder and the flipper those incisions will meet sometimes it's a bit especially in a larger dolphin um these skin pieces can be quite large so you can dissect them into blocks and it makes it easier to remove it then because the blabber is quite attached to the subcutaneous tissue are going to keep those blocks of skin that we are removing because they will be checked for parasites and cordly we go up to about the level of the anus because that's where we will be working until [Music] so once we have taken off the skin we do cross sections into it to check for parasites so the skin that's been removed we cut in a crisscross manner into the blubber up to the skin and these are approximately three centimeters two centimeters apart and we then just open up and check whether there are any parasites in the skin and if you see anything um if you can get a whole parasite or an adult parasite you can take that out and put it into formalin into alcohol the skin sample goes into formalin if you see any lesions you might wonder why we're only doing one side well it's quite representative if the animal has had skin parasites it should be fairly well distributed and doing one half of the animal if it's there we will find them next we're going to start by opening up the abdomen and then the thorax you can feel the the cordal end of the ribs that gives you an idea of where the abdomen starts and basically try and lift the body wall away from the intestine so you don't accidentally cut into them and as you can see there that's the abdomen opened up and then we do a y incision so we go along the coral end of the ribs and then down the midway and pull the body wall away from the intestine so your knife doesn't accidentally cut into the intestine it's important to check for any fluid in the cavities the abdomen and the thorax as you open them there is going to be some fluid in an animal that has been frozen such as this one and then defrosted because there will be seepage from um the organs and then also from the ice as it's defrosted so that is normal if you have a just dead animal freshly dead animal that's on the beach and you see fluid that would certainly be significant in an animal like this that's been frozen and not as much so the blood tinge fluid in this abdomen i would put down to freezing and defrosting so that's the midline and then this is where the last rib is so i'm going to extend this this incision up again being careful not to cut into any of the abdominal organs right up to the spinal cord which is running here this is all muscle so the abdomen has been opened up and if you have a look here this is the diaphragm i'm going to separate the diaphragm from the ribcage and then open up the thorax bone cutters this is quite a small animal so smaller bone cutters are sufficient if it's a larger animal you will need some bigger tools for that try not to touch the organs as you move along we want to open up the abdomen and the thorax and have a good sort of bird's eye view of it and if we see any lesions we'd like to take samples that are sterile as possible and then only start to handle the organs so first open up without handling or touching and try to also keep your instruments away from the from the organs so now i'm going to cut on the top first going to just make a line with my knife and then [Music] so we have the rib cage removed we can sample a portion of the rib bone with some of the intercostal muscle that can be kept for analysis of minerals and it can be frozen so it does not have to go into formalin it goes into a bag and it's just kept in the freezer then and you can do bone ash on that and send it off if there is any concern so there's our rib sample so now we have the thorax and abdomen open as you can see there has been quite a lot of fluid there's also fluid here in the thorax and it's really blood tinged and that is often what one sees with a defrosted carcass move the organs around a little bit to see if you see any lesions and if there are any points of concern especially in the lung you can sample it now already in a sterile bottle with sterile instruments which i will show you how to do now i'm going to show you how to take a sterile sample and even though there isn't a lesion here firstly put your forceps and your scissor into the formula to sterilize it if you do not have sterile instruments that are in a sterile pack so scissor and forceps has been placed into formula and for a bit shake off the excess and let's pretend that we have a lesion here maybe an abscess in the lung and we will sample it and then keep the container the sterile container closed while you are sampling and only once you have the sample ready do you open it place it in there and close it immediately so you minimize the amount of contamination so if we've had a lung abscess it is now in there and it can be center for culture to show you the topography of all the organs here we have the lungs the aorta and if you lift up the lung lobes you'll see the heart and coral to the heart along the ventral margin of the lungs is is the marginal lymph node this is the diaphragm which is overlying the liver these are the kidneys remember dolphins have lobulated kidneys cranial to the kidneys the adrenal gland this is part of the stomach which we will see better once the gastrointestinal tract has been removed and then the intestines that's the right kidney and this is where the testes are they are intra-abdominal and they are fairly elongated that's the epididymis right there and then lastly this is the urinary bladder between the two testes also quite elongated so they are the three organs that lie in the cortical ventral part of the abdomen we can't see the right adrenal right now but it obviously will be cranial to the right kidney over there as in horses dolphins do not have a gallbladder next i'm going to tie off the intestine and the and the stomach and remove that so we separate the meso colon this is the colon remember the anus is over there so the colon is um in that position in that direction separate the mesocolon so that you have place for tying off we do a double tie and then we cut in between the two ties because we don't want spillage [Music] [Applause] once that's tied off we can separate the intestine from the body wall it helps to move the intestine out of the abdomen and to see where to follow this is the mesentery coming down from the aorta all the mesenteric blood vessels so we will separate it there and that's going through the blood vessels that's why it's bleeding this organ over here that's the stomach the organ right coral to it this is the spleen this is the main spleen and then as you can see there's a little organ similar to it same color this is an accessory spleen and this is a fairly common finding in dolphins [Music] so there i have the esophagus um that i've separated as you can see there's the this is the diaphragm and this is the esophagus coming into the stomach and that's where we are going to tie it off so that we can remove the whole gastrointestinal tract [Music] again two two ties and we cut in between the two so there they are and i'm going to cut between them and i'll do the same quarterly the two ties that i made earlier in the cola and now the last attachments muscle onto the liver [Music] so now the gastrointestinal tract is removed and we will lay it out so the gastrointestinal tract has been removed as you can see this is the stomach end they are there's the spleen and the accessory spleen and i've laid out the intestine and on this end um is the colon the intestine of the dolphins are quite uniform macroscopically so it's difficult to tell where the duodenum the jejunum the ilium and the colon start and end that is something that one has to look at histologically just to orientate you these are the different parts of the stomach they have a muscular a glandular and a pyloric part in the fold of the glandular and the pyloric part is the pancreas and you can see it's this pale pink glandular tissue and then that's the start of the diodinum from the pylorus so i'm going to start with the sampling of the stomach and then i will move on to the intestine so take a full sample of the stomach full thickness of the wall and of the different parts this is the glandular stomach that's the muscular stomach and this is the pyloric area that's the start of the diodinum so i will sample it there and remember for formalin you wanted to fix so not thicker than two centimeters i will also sample the pancreas note that the pancreas is l-shaped and sample both inside [Music] lastly i'm going to also sample the spleen for easter pathology now i'm going to sample the intestine i'm going to take cranial mid and cordial when sampling the intestine for histopathology do not take samples that are too long because it will not fix that is sufficient that's cranial mid and i've seen a possible lesion right here which is this black discolored area and i'd like to sample that so i'm going to take a sample right there for histopathology this might be an area of hemorrhage so once the samples for easter pathology have been collected you now open up the intestine and the stomach completely we've opened up the intestine there are a couple of lesions that i'd like to show you this is the stomach so just to recap that's the muscular stomach the glandular stomach this is the polaris this here is the mesenteric lymph node and then the intestine has been opened so looking at the stomach you can see there are these lesions these are ulcers remember when you are doing descriptions in pathology you need to describe shape size pattern color consistency so in these cases you would measure it with the ruler and describe them they are three or four they are five to three centimeters and they are black discolored and they are well demarcated um indented or crater like lesions would be a good description the glandular stomach doesn't have any lesions in this case and then carrying on to the intestine i'd like to show you this animal has a really high worm burden and these are tapeworms and if you can appreciate the number of tapeworms that are present in this intestine so i am going to sample some of these and if you can recall we use alcohol so we will take samples of these worms for identification parasitology and we can put them into the into the alcohol in addition something else i wanted to show you was if you look at the stomach or the intestine contents you see that other than the pink discoloration from the blood you can see this white sort of granular intestinal content this is half digested milk so this is a suckling cough still and that is what the milk looks like when it's half digested and the intestine in this animal primarily has the digestive milk and the and the worms the worms are present throughout the intestine lastly i am going to sample the mesenteric lymph node and a sample of one to two centimeters is sufficient and that's for histopathology informally so now we have the gastrointestinal tract out we can see the rest of the abdominal organs better i'd like to point your attention to the kidneys left and right kidney and lift and right adrenal which is under so left adrenal and right adrenal and in this case these adrenals do look enlarged which may be a sign of of stress i'm going to remove the kidneys and the adrenals now i've detached the kidney up to the cordal pole and i'm going to extend it and you can see the ureters running from the kidney this white paler tube and to the bladder which is this elongated structure here also check that there are no dilatations to indicate that there might be a blockage in the ureter that's the left adrenal lift kidney and that's the left ureter go into the urinary bladder i'm happy that there's no lesion there so i'm going to cut that same on the right and once i get to the quartal pole of the kidney again there's the ureter okay so there i have right adrenal right kidney and that's the the ureter of the little tube running to the bladder i'm happy that that ureter looks okay so i'm going to cut through it i'll cut into the kidneys and the adrenals to sample them and to check for any lesions the adrenal has a cortex and medulla the ratio of the cortex to the medulla should be one to one to one so it's one cortex to one medulla to one cortex on the opposite side i'm going to sample half of the adrenal for histopathology same on the left to sample the kidneys i'm going to just do a mid incision and you can see how lobulated the kidneys are [Music] once i have sampled both kidneys i will do a few more incisions to make sure that i haven't missed the lesion i do not see anything that is unusual there in addition we can sample the kidneys fresh as we did with the rib for mineral analysis and for that we can take approximately one quarter of each kidney and place it into the freezer in a in a plastic bag approximately that much kidney is okay for freezing the next organ i'm going to sample is the urinary bladder i've already checked the ureters so this is the bladder back here and it's elongated and it's between the two testes and this will just sample for histopathology so i'll take a little wedge shape and you can see there's still some urine the next organ i'm going to sample is the liver and this is the liver right here the liver has two lobes in a dolphin and we will sample both left and right once i've removed it [Music] in the liver it's important to check consistency and we do that by making parallel incisions that are approximately one centimeter apart and squeezing it between our index and thumb fingers to to check whether it's harder or softer bearing in mind that it is an animal that has been frozen and defrosted which does affect the consistency a bit and make it a little bit softer so now i'm going to sample approximately a cube of about 1 by 2 centimeters below and again the liver can be sampled for mineral analysis as with the kidney and that can also go into a plastic bag and again approximately a handful is a good estimate to use and i will sample both lobes and put them together so that i have a representative sample so approximately that much liver is sufficient for mineral analysis okay next i'm going to sample the testes this is where i've sampled the urinaly bread right there and there's our left testers and there's the right testers this is the tide of colon over there it is a young animal so the testes are not well formed yet i also take a histology sample for of the diaphragm and lastly before we finish off with the abdomen the last sample i will take is of the larger muscles the axial muscles next i'm going to start with the thorax and for this i need to take out the plaque for getting the plaque out i need to do an incision along the jaw and it will be a v down to the intermandibular space and up the other end remove the skin and then i will be taking out the tongue together with rest of the plaque [Music] [Music] so the the tongue is attached to the floor of the mouth and you need to get it detached and you need to cut all along the edge of the tongue and and separate it from from the mouth to get it out and then while i have the tongue nicely visualized if you look at the margins of the tongue you see these little fronds that's called the fringe and in suckling um young animals this is used to create a negative pressure around the teat while they are drinking so it's in effect has a bottle teat suction effect and it prevents the milk from the mother's teeth from floating away in the water while while the youngster is suckling and this is a good indication of age of the animal if they do not have this fringe then we know that they are already weaned which fits in with what we've seen in the intestine in this animal because the intestine mainly contained other than the worms it mainly contained half digested milk so this is a suckling youngster now i'm going to continue removing the tongue by detaching it further so i've separated the tongue and this is the end of the hard palate ends approximately over there and this is the soft palate you can see it indents and this is where the larynx goes up to the blowhole on the top of the head this right here is bone this is the high weight apparatus and i'm going to cut through that so that i can separate it and loosen the high weight in order to get the larynx out [Music] this is the right highway apparatus [Music] and if you look here this is the larynx and that is the goosebeak it is the larynx of of the dolphin it protrudes into the blue hole and when the animal is not breathing it will be closed and open up and that will connect directly to the trachea and then from there to the lungs okay i'm going to um remove the whole pluck now so i have this the tongue i have the larynx and i'm going to separate the right lung from the thoracic wall and cut all along remember this is the aorta so i will sever the aorta there and then i will remove it as one also notice how the lungs are are quite inflated and they they big and that is also an anatomical difference to our land mammals in that these marine mammals need to have in order to keep their lungs inflated they need to have cartilage and the cartilage is present right down to the smaller thinner airways which is not the case in our terrestrial mammals so the lungs are more spongy and they're more firm in a way um and they feel very different they're not as soft and they don't collapse um and become etalictic as as land mammals lungs would after they've died and especially after they've been frozen you wouldn't see lungs that are this solid looking and spongy okay so lastly we're going to separate the heart is also attached to the body wall to the thoracic wall that's the pericardial sac and i have cut into it already and there's the heart so i'm removing the heart with the lungs and there we have the plaque we have the tongue we have the pharynx we have the larynx with the goosebeak and then the trachea and the esophagus with the lungs and the heart the marginal lymph nodes are on the ventral margin of the lungs midway cranial to cordial and they are routinely sampled next we're going to open up the pluck it's been removed i'm going to start with the pharynx and then move cut open the the lungs and then we'll open up the heart so lifting up the fairings and cutting into this area where the oropharynx is this is a sort of a cavernous area carrying on from there this is the esophagus and through the goosebeak or larynx is the trachea the esophagus in older animals one can often find little bits of fish and fish burns that they've eaten and if you are doing foraging ecology you would want to sample that as well to see what fish they have eaten next i'm going to open up the trachea through the goosebeak or larynx and it is cartilaginous and firm and those tracheal rings go into the bronchi so here's the trachea and those are the two bronchi going to the two lungs and there's also an accessory bronchus that is the small opening right here these animals often have lung worms and it's important to open up the trachea and the bronchi all the way down into the into the lung parenchyma so that you can check for the worms carefully so cut until you get right to the tip of the lungs because they often sit in the smaller airways as well and check carefully that you don't have anything and you can cut into a few of these larger airways as well so sampling the lungs for histopathology you have to sample cranial and caudal as well as ventral and dorsal so i'm going to sample both sides which means a total of four samples try not to squash the lung too much when you are sampling it because it does interfere with histopathology and the the tissue does get damaged and of course if there are any lesions you are going to take those in addition to these standard samples so i've sampled four in total and the marginal lymph nodes should also be sampled and as a recap they are midway between cranial and coral and along this ventral margin of the lung right there the bronchial lymph nodes are located between the two bronchi right at the bifurcation and if you palpate in that area you will find them and they can also be sampled at this point next i'm going to open up the heart the pericardium has already been removed as i took the animal as i removed the plug this is the pericardium right there and with the heart one opens it up while it's still attached to the plug remember to cut the right heart along the edge of the ventricle and the left heart down the middle and i'm going to cut this is the groove between right and left interventricular grooves i'm going to cut all along the edge of the right right ventricle that's the that's the atrium the right atrium and i've gone all the way around this is the parmanji artery going to the lungs i can still see the atrioventricular valves and they have not been cut through so that's one valve you will see the rest once i've opened it up completely the left heart that's the left art i'm going to cut down the middle remember it has two anti-ventricular valves so when you cut through the middle you will cut between the two valves that's the left heart so that's the right atrium the left atrium left ventricle and these are the two valves here there's one and there's the other so i've cut between them when i cut into it and if one goes between these two leaflets of the two valves you enter the aorta so now i'm happy that i don't have any thrombi in the heart and i can remove the heart from the lungs so the heart has been removed from the plaque and this is the left heart with the two valves in the ventricle this is the aorta and these are the aortic valves these are semilunar valves these are atrioventricular valves on the right i've opened it in a circular cut so that we um the ato ventricular valves are not damaged this is the pulmonary artery similar to the aortic valves these are also three semilunar valves to sample the heart we are going to take a sample of the right ventricle the left ventricle as well as the interventricular septum between the two ventricles and again i'm going to take a sample that is not too large so that it will fix in the formula so approximately a 1 by 2 centimeter sample so that's left ventricle right ventricle and interventricular septum next i'm going to sample the tongue approximately midway to take a sample of the tongue muscle and again it's about one centimeter thick and check for lesions and if you don't have any lesions then a standard sample will be sufficient and that's the plug sampled okay next we're going to remove the head so that we can get ready to um get the brain out so if you look at the right side of the animal this is where the eye is and the right flipper is still here approximately halfway between the two is where we will cut to get into the first joint or c1 the atlanta occipital joint also if you move the head up and down you can see approximately here where my finger is that is where the head is joined to the spinal cord and that is where we would like to cut to remove the head start with the ventral part because it's easier to find the mark and if you look in this area i've already gone into the joint of that first vertebra once you have the correct spot it's easy to to continue once the the ventral part has been opened it's easy to to extend to the lateral and dorsal parts of the joint so i'm going to move the dolphin onto the back so now the head has been removed and i'm going to skim this remove the blubber and we remove the excess soft tissue to get to the skull to get it nice and clean before we open up the bone as i am cutting the the mandibular area there is a special fat right here along the ventral and lateral part of the mandible this is called acoustic fat so it is a routine sample and we will take a portion of that acoustic fat in addition to that they also have the melon which is located here in the cranial head and once we've removed the skin you will see that as well and that's also very important [Music] [Music] so this is the the opening of the blowhole and it's in effect the nose of the animal and it also has the ability to close i'm going to sample the melon and collect for histopathology and as you can see with the with the tissue in the jaw it is also mainly fat but it also has a lot of nervous tissue in it now i'm going to try and get as much of the muscle and soft tissue as possible off the skull so that we can get to the to the bone itself [Music] so to know where to cut to get the brain out um this is you can see there's a bulge and that is where the main part of the cerebrum is the cerebellum is below that so cut from where the condyles are towards where the jaw line is or that your angle is and then up towards the blow hole and you're going to cut in in sort of a diamond shape it doesn't have to just be four you can do a few smaller cuts but in effect you would like to get this cap off so that you can keep the brain whole and in one piece so we've opened up the skull and you can see the brain is exposed so these are the fissure lines the fontana lines and it shows how young this animal is the skull has not fused yet as you can see this brain is very rounded and the cerebellum one can't actually see it at this point it is below the cerebrum so now i'm going to remove the brain and then show you which parts to sample [Music] so this is the vengeful view the cerebrum left and right and the cerebellum and the medulla oblongata um going towards the spinal cord and then the brain stem over there and if i try to move it over without damaging it too much that's the dorsal view two cerebral hemispheres and the cerebellum it is quite soft because of the effects of the freezing as well as the young age of this animal so firstly i'm going to split up into left and right brain there are lots of gyra and sulky and lots of folds if you compare to other terrestrial mammals that we normally see the left half of the brain is more intact so i'm going to sample that cut through so this is cranial this is caudal cut through the middle of the brain and you will get the the brain stem and you should also get a portion of the hippocampus if you cut there and i'm going to sample a section from the middle so that i can include that hippocampus and brain stem area the cerebellum you cut longitudinally so that you can see the jarrian and visualize them nicely and that you can also sample together with the brain stem and the medulla in that area and that's the basic samples that we need for the brain okay and that's how you do a postmortem on a dolphin specifically for a field postmortem bearing in mind that if you have a specific study or research you will probably want to take more samples specifically for what you want to study but this is these are the basics that you would need to be able to do and i hope that one day when you get your first dolphin postmortem you'll enjoy it and that this video will be handy thanks [Music] 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