Current understanding of in vivo cervical spine biomechanics and its clinical implications

Abstract

Neck pain and cervical degenerative disease remain major contributors to disability worldwide, and each surgical intervention inherently alters the mechanics of cervical motion. Understanding cervical spine biomechanics is therefore essential for optimizing diagnosis, operative planning, and long-term outcomes. This review integrates contemporary anatomic, kinematic, and clinical evidence to describe how advances in in vivo imaging have redefined the understanding of cervical motion. Techniques such as dynamic magnetic resonance imaging and biplanar radiography now allow direct, three-dimensional quantification of vertebral translation and rotation during physiologic movement. These studies demonstrate that normal motion depends on coordinated coupling among the discs, facets, and ligamentous stabilizers, and that degenerative or postoperative conditions disrupt these interactions, leading to altered instantaneous axes of rotation and changes in load sharing. In vivo findings also challenge traditional explanations of adjacent segment disease, showing that postoperative adaptations reflect altered motion quality rather than excessive hypermobility. These insights provide a biomechanical rationale for motion-preserving constructs such as cervical disc arthroplasty and inform rehabilitation strategies aimed at restoring physiologic coordination. By connecting fundamental biomechanics with surgical application, this review presents an updated framework for interpreting cervical motion in both health and disease and underscores the value of dynamic imaging in guiding the next generation of motion-preserving spine care.