There are five physiological mechanisms which can be used to explain how medical acupuncture works. Each can be used for a different purpose which is why anyone using medical acupuncture must be able to make a conventional medical diagnosis and have an understanding of the underlying pathology to be effective when using a medical acupuncture approach.
The different mechanisms require variations in the treatment technique and so this needs to be tailored to the individual patient.
This blog will discuss the second of the four mechanisms, the segmental effects:
The action potentials which have been generated by the insertion of the needle also travel along the nerve directly to its particular segment (entry point) in the spinal cord where it causes depression in activity at the dorsal horn which reduces its response to painful stimuli. This is called the ‘segmental effect’ of acupuncture and is most likely the main mechanism by which acupuncture is able to relieve pain.
Acupuncture is capable of inhibiting pain signals arising from any structure which sends sensory nerves to that particular part (segment) of the spinal cord. A good example is a pain arising from an arthritic knee. The nerves which supply the painful knee enter the spinal cord at the same segments in the spinal cord as the nerves which supply the muscles around the knee. As such, by targeting the muscles around the knee it is possible to inhibit pain arising from the knee itself.
In addition to the segmental pain-relieving effects, the insertion of a needle may also reduce muscle tension more generally within the area being needled (mainly within the same spinal segments) which may improve muscle function as well as joint mobility.
Summary: Inserting a needle near sensitive or painful joints or muscles may bring about strong pain-relieving effects as well as easing muscle tension.
By Simon Coghlan MSc, BScPhysio, DipMedAc
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