The ear is the spine 1
That's what Alred A. Tomatis thought anyway. And you know what? I agree with him. It sounds like a radical idea until you find yourself teaching voice and observing students singing. What do you see? The spine responds to the voice, in fact, is the voice, but most of us don't think of it like that.
Have you ever watched an amateur chorus do their thing when standing behind a quartet of excellent soloists? Take a good look at the head/neck relationship of the former and then the latter. You'll see that the soloists express a greater degree of verticality.
Tomatis observed that the two little muscles of the ear - the tensor tympanum and stapedius - act like rudders, guiding vibration into the ear as well as integrating the action of the muscles of the body, this being flexion and extension. This is something I have experienced first-hand. While at the Listening Centre in Toronto in 1999 and 2000, I felt a strong reorientation of my spine towards verticality - i.e. extension. What was I doing to affect this? Listening! To high frequencies no less. Surprising? You bet. This brings me to the focus of this post.
I read an article in the New York Times this past week about the work of Esther Gokhale, who does very interesting work in the use of the body, specifically, the alignment of the spine. The curious thing is that, after researching her work and watching a Youtube video of her 'method,' I found, to my surprise, that my posture mirrors her teaching - this after a decade of working with Tomatis' ideas and a vocal pedagogy founded in the teachings of the Old Italian School.