Chapter 22 | Activator Methods Chiropractic Technique (Mosby)

The prevalence and economic impact of acute  and chronic back pain (BP) and the understanding that many BP problems  have mechanical origins have prompted clinicians and researchers to the  search for improved analytic and experimental methods to quantify the  biomechanical characteristics of the normal and abnormal human spine.  This chapter provides a brief review of the biomechanics of spinal  manipulation, which is followed by a detailed summary of the dynamic  response of the human spine to the Activator Method of chiropractic  posterior anterior (PA) manipulation.

Basic Spine Biomechanics: The spinal column combines an  intricate architectural arrangement of bone, muscle, and soft tissue  components to form a structure of mechanical as well as physiologic  significance. Not only does the spinal column serve to protect the  spinal cord but it also transmits, attenuates, and distributes the  static (time-invarying) and dynamic (time-varying) forces associated  with daily activities. Although the spinal column provides the  structures for load transmission and attenuation, the pathways for load  transmission and attenuation may be greatly altered during voluntary  (postural changes) and involuntary (fatigue) activities, producing  unstable and pathologic changes to the kinematic behavior of the spinal  column. Segmental instability and pathology of the spine are believed to  produce abnormal patterns of motion and forces, which may play a  significant role in the etiology of low back pain (LBP).2° The ability  to quantify in vivo spine segment motion or kinematics, tog ether with  the concomitant forces or kinetics, is therefore, of clinical  significance in terms of both diagnosis and treatment of spinal  disorders and back pain.

Reference: Keller TS. Engineering – in vivo transient  vibration analysis of the normal human spine. Section VIII, Chapter 22, pp 431-450, in Fuhr AW,  Green JR, Collaca CJ, Keller TS. Activator Methods Chiropractic  Technique textbook, St. Louis: Mosby, 1997.