Facet Joint Injections in Spinal Pain: A Comprehensive, Evidence-Based Review of Anatomy, Diagnostic Indications, Procedural Technique, and Implications

Facet joint (zygapophyseal) arthropathy represents a highly prevalent but often underrecognized cause of chronic axial spinal pain, contributing to up to 67% of neck pain cases, 48% of thoracic pain cases, and 45% of low back pain cases. Despite this substantial epidemiological burden, the diagnosis remains clinically challenging due to the absence of pathognomonic historical features, physical examination findings, or imaging abnormalities. Consequently, facet joint pain is fundamentally a diagnosis of exclusion, and image-guided facet joint injections have emerged as both a critical diagnostic tool and a potentially therapeutic intervention. This review provides a comprehensive, professor-level synthesis of the relevant anatomy, pathophysiological mechanisms, clinical indications, contraindications, equipment requirements, procedural techniques, complication profiles, and clinical significance of facet joint injections. Special emphasis is placed on the dual innervation pattern of the facet joints (each joint receiving innervation from the medial branches of the same and the superior spinal level), which underpins both diagnostic blockade and radiofrequency ablation strategies. The review also highlights key safety considerations, including the preferential use of non-particulate dexamethasone in cervical and thoracic injections to mitigate embolic risk, and the essential distinction between diagnostic intra-articular injections and medial branch blocks for radiofrequency ablation candidacy. Finally, the critical role of an interprofessional healthcare team—including the procedural physician, nursing staff, pharmacist, and imaging technician—is underscored as a cornerstone of patient safety, procedural success, and optimal clinical outcomes.