Joint mobilization is a manual therapy intervention, a type of passive movement of a skeletal joint. It is usually aimed at a 'target' synovial joint with the aim of achieving a therapeutic effect. When applied to the spine, it is known as spinal mobilization. These techniques are often used by chiropractors, osteopaths, occupational therapists, and physical therapists.
Classification and mechanisms of action
Joint mobilization is classified by five 'grades' of motion, each of which describes the range of motion of the target joint during the procedure. The are generally called Grade I through Grade V (where grade V is the same as manipulation). The different grades of mobilization are believed to produce selective activation of different mechanoreceptors in the joint.
- Grade I - Activates Type I mechanoreceptors with a low threshold and which respond to very small increments of tension.
- Activates cutaneous mechanoreceptors.
- Oscillatory motion will selectively activate the dynamic, rapidly adapting receptors, i.e., Meissner's and Pacinian Corpuscles. The former respond to the rate of skin indentation and the latter respond to the acceleration and retraction of that indentation.
- Grade II - Similar effect as Grade I.
- Grade III - Similar to Grade II.
- Selectively activates more of the muscle and joint mechanoreceptors as it goes into resistance, and less of the cutaneous ones as the slack of the subcutaneous tissues is taken up.
- Grade IV - Similar to Grade III.
- With its more sustained movement at the end of range will activate the static, slow adapting, Type I mechanoreceptors, whose resting discharge rises in proportion to the degree of change in joint capsule tension.
- Grade V - This is the same as joint manipulation. Use of the term 'Grade V' is only valid if the joint is positioned near to its end range of motion during joint manipulation. Evans and Breen recently contested this assumption, in fact arguing that an individual synovial joint should be positioned near to its resting, neutral position.
- Maitland, G.D. Peripheral Manipulation 2nd ed. Butterworths, London, 1977.
Maitland, G.D. Vertebral Manipulation 5th ed. Butterworths, London, 1986.
- How Manipulation Works
- Evans DW, Breen AC. (2006). "A biomechanical model for mechanically efficient cavitation production during spinal manipulation: prethrust position and the neutral zone.". J Manipulative Physiol Ther 29 (1): 72–82. doi:10.1016/j.jmpt.2005.11.011. PMID 16396734.