A cross-sectional construct validity study was conducted to investigate the relationship between clinician-rated cervical passive intervertebral motion (PIVM) testing and ultrasound quantification of cervical interfacet motion. The study was designed to determine whether clinical classifications of cervical segmental mobility correspond to objectively quantified cervical intersegmental movement.

PIVM testing represents a clinician's subjective assessment of cervical segmental movement based on perceived excursion, resistance to motion, and end-feel. In contrast, dynamic musculoskeletal ultrasound (MSKUS) was used to objectively quantify cervical interfacet motion by measuring changes in interfacet distance between standardized cervical positions. Construct validity was evaluated by examining the relationship between these two measurement approaches.