Joint mobilization

Joint mobilization is 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.

Terminology

Mobilization is a manual therapy intervention and is classified by five 'grades' of motion, each of which describes the range of motion of the target joint during the procedure. [ Maitland, G.D. "Peripheral Manipulation" 2nd ed. Butterworths, London, 1977.
Maitland, G.D. "Vertebral Manipulation" 5th ed. Butterworths, London, 1986.]

Roman numerals are generally used in labelling the grades of motion (i.e. Grades I to V). Grade V is the same as manipulation.

Mechanisms of action

The different grades of mobilization are believed to produce selective activation of different mechanoreceptors in the joint:PDFlink| [http://sunzi1.lib.hku.hk/hkjo/view/47/4700061.pdf How Manipulation Works] .

* 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, ie. 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.

: By virtue of the large amplitude movement it will affect Type II mechanoreceptors to a greater extent.

* 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 [cite journal | author = Evans DW, Breen AC. | title = A biomechanical model for mechanically efficient cavitation production during spinal manipulation: prethrust position and the neutral zone. | journal = J Manipulative Physiol Ther | volume = 29 | issue = 1 | pages = 72–82 | year = 2006 | pmid = 16396734 | doi = 10.1016/j.jmpt.2005.11.011] recently contested this assumption, in fact arguing that an individual synovial joint should be positioned near to its resting, neutral position.

References

See also

* Joint manipulation
* Orthopedic medicine
* Osteopathic Manipulative Medicine
* Chiropractic
* Physical therapy