Vertebral Artery and Cerebral Hemodynamics After Various Head Positions & Manipulation in Patients With Neck Pain

Each participant will undergo three separate test maneuvers. Neutral (0° rotation) neck position (condition 1) will be followed by block randomization between maximum voluntary rotation (condition 2) and a high-velocity-low-amplitude cervical manipulation targeted at C1-C2 (condition 3). Conditions 1 and 2 will be held for 1 minute before returning to neutral alignment. For the manipulation, the head will be repositioned at neutrality immediate. An experienced practitioner will perform the manipulation on the adjustable and pivotal MRI bed. After each condition, MRI of the upper neck and cerebrum for perfusion and blood flow will ensue.