Axial Block (AxB): A Position Paper on Definition, Terminology, and Pathophysiology

The purpose of this position paper is to establish a unified terminology and pathophysiological framework for Axial Block (AxB). The Axial Organ (AxO) is defined as a continuous biomechanical and neurophysiological system extending from the pelvic ring to the skull, while the Axial Corresponding Functional Unit (AxCFU) denotes the integrated anatomical and functional complex associated with each articulation of the AxO. AxB is defined as an articulation-centered functional disorder of an AxCFU characterized by a mechanical constraint and impaired physiological joint motion. Within the proposed pathophysiological model, altered articular congruence, including transient or persistent malposition, represents a principal biomechanical feature, while the affected AxCFU may act as a peripheral source of altered afferent input. AxB does not itself constitute Persistent Afferent Bias (PAB), although persistent altered input arising from an affected AxCFU may contribute to its emergence or maintenance within the broader Somato-Psychic Pathway (SPP) framework. The paper distinguishes multiple Axial Blocks (AxBb) from an AxBb Chain, defined as a biomechanically and neurophysiologically interconnected organization of AxBs that behaves as an integrated functional unit. Recurring clinical observations underlying the framework include the predominance of AxBb over isolated AxB and the coordinated persistence, recurrence, release, and progressive extension of AxBb Chains. Mobilization, unblocking, spontaneous reposition, reposition, and functional restoration of the AxCFU are defined as distinct processes or outcomes that may participate in AxB/AxBb resolution. These distinctions are intended to standardize terminology rather than to prescribe a universal treatment protocol or establish therapeutic efficacy. Each concept is presented through a primary definition, explanatory commentary, and defining characteristics. The proposed nomenclature provides a common basis for clinical communication, mechanistic research, and empirical validation of the AxB framework