For almost as long as I was in it, fandom was under the impression that Avatar and Recombinant characters have their tswin, or neural queue, attached lower than Na'vi, right above the neck, when Na'vi have it from the top of the head.
I drunk that kool-aid and defended it myself. However, further inspection proves it's wrong.
Firstly : Metkayina very clearly have their tswin starting at the back of their skull, on a low point. It's most evident with kids :
But we can also see it in these two, especially the bully, who has his tswin literally sticking out :
Shots of the Ta'unui completely nail the coffin :
The top of his head is braided but there is no sign of a bulge and the tswin sits under the bulk of the hair, and is gripped near the neck.
This of course takes the cake :
So it seems the tswin comes from the back of the head for them. Could the Omatikaya be different? I don't think so.
Neytiri clearly doesn't have the very low placement we see in other, but there is also no indication that her tswin comes from the top of her head. No bulge to accomodate this.
This shot of her after dismouting her ikran is the best view of it poking out and the attachment point is clearly bellow the back of the cranium.
Looking at Omatikaya fashion in general...
I feel like it's pretty clear that they favour heavy braiding with shaved sides. The men in those shots have very thick braids at the base, from gathering hair all the way from the top of their heads. I think this provides extra protection for the weak base of the tswin that we know has brainy bits...
But my conclusion is that this is a fashion style!
Na'vi, recoms and avatars all have tswin origination from the back/lower back of their head and the differences aren't great, and obfuscated by hairstyles.