Effects of Manual Therapy on Blood Flow

Abstract: Effect of Selected Manual Therapy Interventions for Mechanical Neck Pain on Vertebral and Internal Carotid Arterial Blood Flow and Cerebral Inflow

Lucy C. Thomas, Darren A. Rivett, Grant Bateman, Peter Stanwell, Christopher R. Levi


Manual therapy of the cervical spine has occasionally been associated with serious adverse events involving compromise of the craniocervical arteries. Ultrasound studies have shown certain neck positions can alter craniocervical arterial blood flow velocities, however, findings are conflicting. Knowledge about the effects of neck position on blood flow may assist clinicians avoid potentially hazardous practices.


Twenty healthy participants with a mean age of 33 years were imaged using 3T MRA. All participants had normal vascular anatomy. Average inflow to the brain in neutral was 6.98 ml/s and was not significantly changed by any of the test positions. There was no significant difference in flow in any of the four arteries in any position from neutral, despite large individual variations.


Blood flow to the brain does not appear to be compromised by positions commonly utilised in manual therapy. Positions using end-range neck rotation and distraction do not appear to be more hazardous to cerebral circulation than more segmentally localised techniques.

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