Within the depth-psychology corpus, ‘spine’ operates across at least three distinct registers that rarely speak directly to one another yet converge on a shared concern with the body as the seat of psychological structure. In sensorimotor psychotherapy, as elaborated by Pat Ogden, the spine is treated as the literal axis of postural and psychological organization: its curves, rigidity, collapse, or lengthening serve as somatic signatures of trauma, defensive states, and relational capacity. The spine’s developmental history—from the neonatal C-curve through the acquisition of cervical and lumbar curves—maps onto the developmental history of the self, and therapeutic intervention frequently targets spinal alignment as a means of reorganizing affect and cognition simultaneously. In Jungian typological theory, John Beebe employs ‘spine’ as a structural metaphor for the axis connecting the superior and inferior functions, the organizing backbone of personality around which individuation turns. Ancient sources—Plato’s Timaeus and Onians’s survey of Greek thought—position the spinal column as the conduit of marrow, the ‘stuff of life,’ lending the term a cosmological and sacred resonance (the os sacrum, the ‘holy bone’). Neurobiological authors such as Craig and Kandel treat the spinal cord as the foundational processing structure of the central nervous system, linking peripheral sensation to homeostatic and emotional regulation. The term thus spans phenomenology, typology, mythology, and neuroscience, serving in each domain as a figure for the central axis of living organization.