Background: Acupuncture has a long history of relieving many forms of pain. However, many of acupuncture's mechanisms are still unknown and/or misunderstood. Objective: This review looks at past research on many different methods and targets of study related to acupuncture. The main focus is upon the importance of connective-tissue planes in and around acupuncture points. Method: Relevant articles from journals as well as books on the topic were searched manually for information related to the topic. Results: Various studies offered different (and sometimes interrelated) mechanisms for how acupuncture needling results in analgesia among other effects. Emerging evidence, however, has shown the increasing importance of extracellular matrix rearrangements that result in lower mechanical stress states of surrounding tissues. This leads to lower constant stimulation of regional mechanoreceptors, in turn, reducing chronic pain and discomfort. Conclusions: The extracellular matrix has emerged as an important area of study on the effects of acupuncture needling.