can p&f stretching help rectify spinal subluxations and or help open the intervertebral spaces?

In short, yes to both. Here are the mechanisms:

Subluxations (described as 'partial dislocations' in the Macquarie Dictionary) are said to have occurred when they are able to be rectified by manipulation. There are references to this phenomenon in all editions of ONBP. One might not find this circular argument persuasive—but none of the many happy patients of chiropractors have any problem with this.

When I was asked to speak at the Chiropractors and Osteopathic College's National Conference a few years ago, I discussed this very question. I asked, 'If subluxations are real, what is their cause?" Some answers are LLI, asymmetrical lifestyle activities, and so on—all the things ONBP addresses in detail.

Spinal subluxations are caused by muscles and ligaments pulling on bones; this can happen quickly (trauma) or slowly (lifestyle). The right kind of stretching can change this tendency. Balancing the symmetry of the body (in terms of patterns of flexibility and strength) is the fastest way.

IMHO, intervertebral spaces (let's be specific: the ones that are significant for back pain are the intervertebral foraminae, the spaces that are formed by notches in the bottom and top of adjacent vertebrae, and through which the segmental nerves pass), CAN be increased ("opened") by both movement and reduction in the held tension of the spinal and other key muscles. As well, in this scenario, the disks themselves (whose loss of height is one of the causes of these spaces narrowing) are able to regain much, and sometimes all, of their normal height. Even diseased disks can benefit.

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Kit Laughlin
www.pandf.com.au
www.bodypress.com.au