The literature on prosthetic rehabilitation has, since the inaugural edition of Prosthetics and Orthotics International in 1977, repeatedly emphasized that the success of physical prosthesis depends less on mechanical fit than on the psychological process by which the amputee comes to invest the device with selfhood. Desmond and MacLachlan, in their 25-year review of the journal, articulated this as the prosthesis becoming a "psychically invested aspect or extension of self" [1]. This essay proposes that the same architecture describes what occurs spiritually after trauma and post-traumatic stress disorder (PTSD). The pre-traumatic self is amputated; what fills the absence is not merely an external theological or ritual replacement but a structure that must be psychically invested before it can become constitutive of selfhood. I term this construct the spiritual prosthesis. Drawing on the clinical literature on prosthetic adjustment, contemporary trauma psychology, Lurianic Kabbalah, post-Holocaust theology, and my prior work on hermeneutic medicine [2-11], I develop five parallel axes between physical and spiritual prosthetic integration: disruption and reconstruction of the inner imago, symbolic ambivalence, phantom phenomena, cosmesis versus integration, and lifespan fluctuation. I then confront the strongest objection to the metaphor — that physical prostheses are fitted from outside while spiritual reorganization is irreducibly internal — and argue that the asymmetry collapses under scrutiny of the prosthetic literature itself. The essay concludes with clinical implications for trauma-informed hermeneutic medicine.