As dragons are mythological creatures, any anatomy present here is taken from word of mouth, books, or knowledge from dragon therians.
Because of the fact that dragons are considered mythical, there are no real known specimens of a dragons skeleton, so we're going to have to compromise. I'm using the example of times when I've mentally seen Lyxran, therefore estimating the skull from his physical body traits. The dragon's skull is somewhat like a Komodo, only more armored and bulky, with the snout being longer.
The horns on top of the head, believed to connect or actually be the skull, are actually not made out of bones. They're made of Keratin, the same protein as our nails, a rhino's horn or horses’ hooves. You have to think about it if they were connected to the skull. Like nails, the dragons horns will chip or even break off, and the dragon would suffer very major injuries if the skull was the prime source, because it's what holds the brain and other vital substances. However, special nerves and muscle attach the horns to the head, and I believe those nerves lead directly to the brain. Why? Because dragons might use their horns for defense or dominance, like a ram. If they were to be attached to the skin and nothing else, they'd easily be knocked or ripped off.
Dragons are known to have slightly long necks that can swivel around 180 degrees to view directly behind them, which is a good ability to have if your on the lookout for prey or something. The necks aren't giraffe big, but they are slightly slender. However, some species, like Lyxran, have short necks, only a bit longer than a human. They're types have limited angle direction, probably around 105 degrees.
The dragons’ teeth are similar to all the other carnivores out there. The jaws consist of incisors, canines, molars and premolars. An example I'm going to use will be the wolf. Like the wolf, dragons have 2 upper-canines and 2 lower-canines that are longer than the rest. These are of course used to tear off large pieces of flesh, as well as to hold onto prey so they don't get away. Other than food uses, the canines can be used to scratch small places that the walking appendages can't reach, such as the neck or appendages themselves. This action is similar to a domestic cat actually.
The incisors, located in between the canines, are used to just grasp the prey instead of cutting through flesh. The molars and premolars, taking up both sides of the back teeth, chew the meat, though dragons aren't known for chewing too much. Their throat muscles allow the reptile to swallow big amounts of food at a time, though let's talk about that later on, ne? xD
Here's a little fact of the dragons teeth. The jaws are covered in a metal coating, not enough or the kind to make them feel like lead, but the metal is definitely there. Because of this, when someone first successfully shifts into a dragon, a copper-like taste is in your mouth that goes away after time, so don't worry :3 That's normal. The reasons for the metallic traces are explained later on though.
I admit, I know next to nothing about the eyes of a dragon, and Lyxran isn't with me right now because he's doing whatever it is theriotypes do when they aren't communicating with you, lawlz xD I'm taking a wild guess here, but I sense that a dragons eyes are like felines, being able to see in the dark and whatnot.
Dragons, or at least Lyxran’s species, aren't excellent at seeing in unlit places like the felines level, but they still have the ability. Like a cat, dragons have slitted pupils which change size according to the amount of light being let in. They dilate in the sun while they widen at night.
Dragons eyes are surrounded in a special set of small, overlapping scales. They aren't in the way of the actual sight line, but they accommodate the outline of the eye. These scales are humans’ eyelids. Yes, dragons do blink xD They also prevent too much moisture or heat from getting in the eyes. The scales are 'filled' with nerves, so they're also sensitive.
Colors: Eye color can range from gold to red. Dragons’ eyes can be yellow, gold, red, green, blue or even a mix of 2. The pupils are or course black.
It comes to my attention that parians don't entirely know much about the ears Internal, external, none at all; It's just a big blur, ne? Well, those answers are actually all correct.
Some species have internal ears; just like a bird does. They look like small holes buried on both sides of head, sometimes covered by scales. Despite their size and condition, dragons have a good sense of hearing. When sounds entire the ear canals, the sound waves travel through special nerves and muscles where they reach the brain, before the noise is then processed.
To be honest, I might have to skip how external ears work because Lyxran has internal ears so I have no experience or personal information. When a dragon has external ears, some people might call them 'head fins' because they look discretely like really thick fish fins.
They consist of small spines that are connected with a thin leather-like material. Similar to a fin, ne? xD That's... really all I know about external ears... gomenasai! My guess is they work the way internal ears do. Instead of scales preventing certain sounds from entering the canal, the ear leathers (?) do.
Perhaps the external flaps work the way an animal’s ears do, swiveling around to certain angles so the hearing can be limited towards that direction. Think of a cat. When they hear a sound to the left, their ears automatically twist around so the canals are pointed in that direction, allowing the feline better hearing of that certain noise. It's a possibility, is it not? xD
What's there to really say? A dragons tail can vary from a long, slim appendage to just a really small stub. They're used for multiple purposes, each in totally different categories; flying, defense and mating.
Flying: Dragons can use their tails to coordinate themselves in the air when flying. When they go left, they swipe their tails to the right, where the sudden rush of air tugs their body in the opposite direction. However, this coordination skill also involves the dragon turning it's torso and front legs in the general angle too. The tail merely directs the rear of the reptile to turn.
Defense: If you haven't already guessed where I'm going with this, I mean the tail is used as a personal weapon: a whip. The dragon lashes its tail out in the direction of prey or predators to deliver a powerful blow that can be fatal or not; whether it be a warning shot or something to deliver a kill. The thinner the tail is, the more smack it's going to be, while the power itself increases with how thick it is.
Mating: This isn't a topic Lyxran really tells me about, or even what I wanna think about xD Buts it's gotta be done, ne? Dragons might show off their tail the way a peacock does. They... seriously, I don't know how this works so let's skip xD
A variety of dragon species have little spikes that are located along the outline of the spine, ranging from 3cm to 7cm. They can be any color possible, though they're often related to the shade of the body scales. The spikes can be hooked, straight or even all connected; the possibilities are really endless. Like the head/face horns, a dragons spines are made out of Keratin; again, the same protein nails are made out of. If they were connected to the actual spine, when the dragon rolled or was fought onto its back, the vertebrae would shatter and it would probably result death. The source of this estimation comes from the prehistoric dinosaur, Spinosaurus.
Western Dragons are known for their large wings, the beast being the only recorded reptile to fly. Like external ears, the wings consist of long spines that are held together by a material that greatly resembles leather. There are usually 3-4 long spines on each wing, but perhaps there might be certain species with 7 spines, who knows?
The wings are located on the back, specifically close to the shoulder blades. In case your wondering, Wyverns are the species whom have wings for front legs, not Westerns.
They're usually bigger than the entire body of the dragon so in flight, they can properly keep in the air. The body of the dragon is still heavy because of the coat of scales and the only-partly hollow bones. Because of this, the wings absolutely must be quite large to accommodate the reptile; otherwise the dragon won't even be able to lift off the ground.
When they're not in use, dragons fold up their wings tightly. How can I really explain this, you've seen pictures! Dx
A dragons hearing isn't perfect and it can't hear a tiger growl from hundreds of miles away. However, they can hear pretty well. Dragons have evolved so they could be a top predator, and having accurate hearing is pretty important for that. I've already explained how the ears actually work, so go there before you read this xD Sense rate- 7/10
A dragons nose is very sensitive, as is every other reptile out there. The sense of smell isn't very accurate when it concerns smells of something specific, but when there are a range of scents, the dragon is pretty good. To be honest, I don't think smelling is the dragons best sense. In fact, I'd say it's the worst xD When a dragon flies, the nose isn't entirely required like the eyesight or hearing, and since a dragon flies for a majority of its lifetime, the sense is quite weak. Sense rate- 5/10
The sight is definitely the best sense a dragon has. The pupils indeed dilate in bright places so they don't wince and get headaches (it's possible lawlz.) When it's night, the pupils increase in size and so, their surroundings are seen. In the air, an invisible glass-like covering encases the eye so the wind doesn't irritate them and temporarily blinds the dragon. This covering helps with the sun and moon as well. Sense rate- 8.5/10
This lesson will involve both the taste and how they eat etc. The dragon isn't used to sweet things, so they depend solely on the sour and salty taste buds. Dragons or Lyxran's species at least, are carnivores, so they feed on animals of large size such as horses (sorry pollz) or water birds. It actually all comes down to size and location.
Like I said in the teeth section, dragons, like wolves, can swallow large amounts of flesh at one time without regurgitating it up, though they occasionally will if bones managed to go down as well. They don't depend on chewing much, rather using the canines to tear off reasonable chunks of meat.
How dragons act-
Like humans, it can really depend if they're in a good mood or not. Actually, I can't say I'm right when I say this, because Lyxran is just one dragon... But dragons are wise and intelligent. They tend to know a lot about their own species or territory. Yes, dragons like to keep their own territories. They're very protective of them, and can often fight over land. They're just prideful like that, ne?
Dragons have short tempers. One second they can be calm and tired, but if someone hurts their mate or dragonling, they turn vicious. The reptiles aren't known to take a liking to everything they pass, but when they do, they remain loyal until the trust or bond is broken. Older dragons don't like to play or fool around, but newborns and younger dragonlings definitely do.
Dragons prefer to stay alone, so they're solitary creatures like a tiger; only seeking mates when in season. Lyxran's species doesn't travel in packs or even in 2's. They are lone wolves. When a couple do get together and have a litter of dragonlings, both parents take care of them for a while, before the male flies off and doesn't come back (Ooh, tough love, ne?) It's exactly like a lot of other reptile and even mammal species.
Dragons act a lot like wolves; they growl, snarl and all things in between. When they feel threatened or a predator comes a long, dragons let loose a deep, throaty growl. If whatever the threat is doesn't go away, it snarls for a few moments, the intensity rising with more time passing. They attack if that doesn't work.
When they're in defiance or annoyed (but at those they love, not an enemy) they kind of snort through their noses, as if they were saying "God, just shut up already" xD
Just to clear it up, dragons don't cool off my panting like a dog; instead they take a long fly or swim. Anyways, when dragons are angry, they bare their teeth and snarl. When they're happy, they don't really express anything, but their eyes always shine, so you'll just know :3 When the beasts are sad or upset, they tend to sleep a lot, and they keep their heads down.
How dragons fly-
Most people believe that dragons depend dominantly on wing power and all of that stuff. But they don't know that a majority of a dragon’s flight is internal. Dragons have a large organ located in their chest/torso called the 'Fuel gland.' This isn't in any modern day species, as this organ is the sole purpose of how they can breathe fire. Because of the fact that this gland is quite large and hollow, it takes a lot of weight off the dragon. This substitute for a birds hollow bones, even though the skeletal system of the dragon is partially hollow. This allows the dragon, a large reptile covered in thick scales, to fly. But of course, the wings are indeed involved, so don't think they aren't :3
How dragons breathe fire-
Let's go back to that 'Fuel gland' which helps the dragon take flight. As I said, this gland is the reason as to how the reptile can breathe fires and other elements. Different gasses are stored within the F.G (Fuel Gland) which comes from the substances the dragon eats. Think of this as an example- A human drinks lemonade. The gasses and carbon in it makes the human burp. For dragons, instead of burping, they breathe fire. Simple as that, ne?
When a dragon eats a zebra for example, the flesh passes by the F.G because it's attached partly to the Esophagus. Before it reaches the stomach, the gasses located in and on the flesh of the prey are somewhat forced out by certain muscles. These are then stored internally in the F.G.
Ignition is also a key factor in the process of fire-breathing. When the dragon wants to breathe fire, it opens its mouth and exhales. The gasses in the F.G travel up the Esophagus and into the open air through the dragons’ jaws. However, before the gasses are released, the reptile snaps its teeth together which ignites the gasses in fire, thanks to the small metal traces stored around the teeth. So I guess you can say the teeth act as a lighter, ne? xD