Petach 71 reads, the arrangement of the lights, i.e., the Sephirot, of the Partzuf, their interconnections and everything about them are just like the arrangement of the limbs and organs of a human body. That’s to say that everything that exists in man i.e., when it comes to his organs, has a corresponding aspect in the lights in the Partzufim above .
As Ramchal points out in his comments here, “this corresponds to the mystical understanding of (the often cited verse that reads) ‘from my flesh I perceive God’ (Job 19:26)”, which has allowed many Kabbalists to grasp the makeup of the upper realms by inference.
In fact, as Ramchal continues in his comments, “it’s in the Partzufim (alone) that we find this differentiation into particulars, not in the Sephirot”. That’s to say that it’s the complexities and subtleties of the Partzufim that allow for analogies which the relative straightforward and linear makeup of the Sephirot would not.
 Also see Klallim MiSefer Kinat Hashem Tzivakot 9 and Iggerot Pitchei Chochma v’Da’at 3.
(c) 2014 Rabbi Yaakov Feldman
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