Frisiangal, I don't wish to debate you on the particulars of medical astrology on Kate's thread-- dedicated to her particular issues. I've put forth a conciliatory view that more than one system is credible. Do you disagree? Maybe a new thread???
Did you have a chance to read the material I linked above on the "man of the signs" (the "zodiacal man"?) I also use Rex E. Bills, The Rulership Book, BTW.
Jane Ridder-Patrick, A Handbook of Medical Astrology, 2nd ed. p. 99 says that Leo rules "the heart, the spine, and the eyes." Also the cell nucleus. "Disorders of the spine or spinal chord" belong to Leo. She gives a varied list of Aquarius rulerships, but none of them relates to the spine, (unless I missed something.)
If you wish, I can quote Nauman verbatim, but I believe I accurately paraphrased her.
The Parkers' Compleat Astrologer was one of the first astrology books I purchased. I think it's fine that they're into polarities, but obviously, not every professional astrologer is. P. 27, incidentally, says that "The sun traditionally rules the heart, back, and spinal column." P. 30: "When thinking about the sun-sign, always look, too, at the polar or opposite signs, which is important and revealing."
Do I agree with everything they wrote in their 6 pages on medical astrology? No. While I think many health problems are caused or exacerbated by one's psychological/emotional state, I don't think that's true for many injuries and illnesses.
They also say to look at progressions, something I didn't do but could for Kate's nativity.
Thanks for drawing our attention to the Aquarian Ebertin degrees.
The Ebertin degrees that I linked on-line, above, seem to have a typographical error for Aqua 17-21, but Ridder-Patrick gives the lot to the "spinal nervous system."
I'm not seeing a "ping" with these degrees on the surgery date chart, but Kate's natal, with Mercury at 19 Aquarius, is within that zone. I'd be curious to learn whether previous injuries or surgeries hit that sensitive degree.
But we already knew from the get-go that Kate has major back trouble.
Interestingly, Ridder-Patrick cites an alternative anatomical degree system (Wemyss) that incorporates polarities, but it gives those Ebertin degrees entirely to the skin!
Which is why I think, that while it's possible to be erroneous in matters of analysis, clearly there is more than one method of chart interpretation in modern western astrology; let alone in comparison to Vedic and traditional western.