Of course I’ll clarify. Yours are very thought followups.
On your first point I’ll need to split it in two halves (two wholes actually). The first is that my reference to residue was not at all a reference to toxins in the body. I was referring to that which is felt in the body, that which occurs as a result of the pose. And that is as much a process of looking as it is a process of experiencing. Ergo the mining of the residue or “left-overs” is just as important in the process of Yoga as finding (or experiencing) this or that.
The second half is the concept of toxins and how that is presented as part of a yoga practice. Just as “counter pose” is a common term so too has it become common to refer to toxins being moved, purged, released or expelled. It is is not untrue that a certain practice effects toxicity in the body. But so does 50 jumping jacks in a sweat lodge or a juice fast.
Obviously the human body has methods for dealing with toxins - sweat glands, bladder and bowels, the lymphatic system, the circulatory system and respiratory system, etcetera. Also there are cleansing processes (shatkarmas) in Yoga as well.
Unfortunately we, as yoga teachers, do not always take our craft seriously enough to continue and deepen our studies. Instead we rely on scripts and books and printed sequences…and something we were told or heard. So the responsibility rests with us not with the students.
On point number two you make a very valid case. A dividing line would be difficult to ascertain as the nervous system goes from the spine to the surface of the skin. Point well taken. However, just as deeper muscles are tougher to work AND hold stronger deeper emotion, so too is the spine the hub of the nervous system and its needs would be different than the needs of your quadriceps or triceps. Carelessness around the spine can result in very serious injury and serious disruptions. Carelessness with the wrist, less so.
But certainly in an asana practice where wrist extension is worked over and over again, a mindful teacher/student would blend in some wrist flexion. Yoga itself is about countering our nature, not adding to it:-)