A fundamental premise on which the clinical practice of chiropractic is based is that misalignment of bones (vertebra) and/or dysfunction in the movement of the bones in the vertebral column or spine produces dysfunction in the nervous system, which leads to ill health and disease. These vertebral misalignments are referred to by chiropractors as vertebral subluxation and may be present in humans or animals.  

Recent work in our laboratory suggests that vertebral displacement/misalignment in the neck can influence the nervous system. However, it remains to be determined if these effects are normal responses as might occur in daily activities of living or are in fact likely to cause dysfunction that is consistent with ill health or disease. 

The general aim of this study is to determine if a vertebral subluxation in the neck, as proposed by the chiropractic vertebral subluxation hypothesis, alters the characteristics of postural reflexes that are normally elicited by some neck movements. 

The study will be performed in adult rats that are first anaesthetised. Recordings will be made from muscles or nerves in the forelimbs while simultaneously moving the upper part of the neck. The effects of moving the neck should normally induce activity in specific muscles and nerves. The characteristics of this response are well defined. We will examine if the existence of a vertebral subluxation in the upper neck changes the characteristics of this neck-evoked reflex response in a manner that suggests dysfunction in the control of posture. We will then reduce the misalignment or subluxation and examine if the characteristics return to the pre-subluxation state 

This study will determine if vertebral subluxation in the upper neck influence neck evoked postural reflexes in a manner consistent with dysfunction and or ill health. Furthermore, it will determine the relative amount of misalignment necessary to cause changes in the characteristics of the reflex. Importantly, it will identify if the reduction of the vertebral subluxation produces normal characteristics in the reflex. 

Grant Value: $60,494
Chief Investigator: Dr Philip Bolton – University of Newcastle
Status: Complete



  • Australian Neuroscience Society, January 2005. Perth Australia.
    Bolton PS, Holland CT (2005) Response characteristics of deep paravertebral muscle spindle afferents to vestibular movements in the neck of the cat. P127, Perth, Australia
  • 7th International Congress of the Musculoskeletal Physiotherapy Association of Australia. November 2003. Sydney, Australia.
    Bolton PS (2003) Laboratory studies of neck afferent information and their clinical implications.