So I'm currently reading Gregor Maehle's Pranayama : Breath of Yoga, which so far (only a couple of chapters in) seems an excellent treatment of the subject, thoroughly grounded in the ancient texts. I love how he's constantly mentioning, quoting, paraphrasing and directing your attention to different Upanishads, Puranas and other shastras, love being able to go to the primary sources and to take a look at the context, you'll come away with a long reading list of works you'll want to take a look at.
So an interesting section in Gregor's book that I just came across deals with Svara, and how you change the dominance of the right or left side of the brain through use of the breath and trigger points in the armpits. There was a big Ahhhh moment when he mentioned Yogadandasana an Advanced B asana that I practiced a while back and always liked but found curious never understanding why it contained dandasana in the name. Well here's why....
|Lord Shiva with his danda|
Perhaps I should work at the asana again....or buy a stick, or a wad of cotton wool which would be a lot easier and far more comfortable.
|Seems you can actually buy these|
*Obviously, just because I can do a fair impression of yogadandasana doesn't by any means suggest I'm an 'advanced yogi', it just suggests I have flexible hips. I like how Krishnamacharya uses 'Proficient' for postures such as these, rather than 'Advanced'. It makes more sense to refer to a relative or certain proficiency in a type of asana, hip openers, backbends, arm balances say, than sugest Advanced yogi status on account of some fancy shapes.
Here's a link to a page that goes into more detail on Svara.