how do cannulas work?

I was thinking about the Nasal Air that uses canulas. I seem to think canulas are thin, so how does the air go down your throat instead of out your nostrils? I can see how nasal pillows would keep the air in your nose because they block the openings of the nostrils, but canulas don't. I'm thinking of the canulas people use for oxygen. I get sores from nasal pillows, do you think canulas would cause sores or do they go up higher in the nose?
As you can guess, I'm a very frustrated cpap user. One year later and can't get the right mask.

I love the Nasal Aire II and the Oxygen canullas drive me crazy. Yes they go in the nares (holes in your nose) and they come in sizes to fit the holes in your nose. Seal against the inside of your nose. I got a little soreness in one side when I first started but Ayr Gel made it go away in a short time. The NAII gives me so much freedom and no closed in feeling.

Jerry

The cannulas in the NA II (my second favorite mask) go into your nose and are a very tight fit. You have to work a bit to get them in at first. Babette has some good posts about this that helped me.

The main thing is to make sure you get ones that are large enough. I wore a medium in the Swift, but in the NA II, I wore a large size cannula, though with the sizing star I thought that was too big.

The reason they need to be so big is so they will fit tight and avoid leaks while remaining at your pressure.