This is worth knowing about: William J. Broad, a science writer at the New York Times, reports that some yoga poses, far from soothing your achin’ back while spiriting you to meditative nirvana, can do some serious damage, ranging from the very painful to the fatal. Take a look at his report. If you do yoga at all, you’ve probably been in at least some of the poses he describes.
Personally, I’ve never felt inclined to stand on my head, nor have I attempted the upward bow. But most of the others—the vajrsana, the extended side-angle pose, downward-facing dog, the cobra pose, the shoulder stand—are things I used to do all the time and still do occasionally. Broad describes neck, back, tendon and vascular injuries and even strokes (among very young people) as direct results of overdoing these basic, simple postures.
Our yoga instructor, who used to conduct classes in my home, often said that if you feel even the slightest pain, you should stop immediately. She urged the budding yogini to avoid poses that were painful or uncomfortable.
Looks like she was right.
So be careful on that yoga mat. Stay out of poses, such as standing on your head or shoulders, that inflict pressure on your spinal column. Don’t push yourself, and don’t get any egotistical ideas about “working through the pain.” The gratification is hardly worth a year or two of physical rehab—or a permanent disability.
Image: Originally posted to Flickr by zivpu at http://flickr.com/photos/57986783@N00/53793280. Creative Commons Attribution-Share Alike 2.0 Generic license.

I hope this doesn’t show up twice. It’s all very true. I’ve hurt myself doing yoga. Now I’m lucky to have teacher who constantly reminds us to come out of poses immediately if we have pain, suggests modifications for those who need them and in general keeps an eye on us. As with any kind of physical activity, you need to know your body and take care of it and having a teacher you trust is huge.
I agree with your teacher! I teach the same way! If you have to think at all about a pose or that you’ve just started doing a particular posture, one MUST use extra precautions! I stress this to my students all the time! And its up to the yoga teachers not to force anyone. Now its not all teachers fault, its also the students fault as well. Egos + Yoga = Injury! Don’t do something you just aren’t sure about!
Thanks for your post and thanks for informing your readers!!!
That said, I would add that yoga rules. Done mindfully and carefully, it will change your body and your life.