Acupuncture is the selection and manipulation of specific acupuncture points by a variety of needling and non-needling techniques.
Acupuncture has been a key component of traditional Chinese medicine for centuries, most commonly used in the treatment of pain. While there is a diversity of theoretical models and techniques that are all described as acupuncture, all models and forms seek to treat symptoms and conditions through either the insertion of needles or "needling" at specifically chosen points on the body, or other "non-needling" techniques focused on these points.
Modern medical acupuncturists choose anatomically and physiologically important treatment points which may include both traditional acupuncture points and other non-traditional fixed points. More attention is focused on the tissue level (e.g., muscle rather than skin) and the type and amount of stimulation given.
There are several variations to traditional acupuncture, including shallow needling, intradermal needling, or intramuscular needling with or without a sensation of numbness, tingling, electrical sensation, fullness, distension, soreness, warmth, or itching felt by a patient around an acupuncture point. Acupuncturists may additionally seek a sensation of tenseness or dragging to the needles obtained by twirling, plucking or thrusting of acupuncture needles. There are also numerous variations of manually or electrically stimulated "needling" techniques, as well as multiple "non-needling" acupuncture techniques.
The mechanism of action of analgesia secondary to acupuncture is unclear, possibly multimodal. However, there are some physiologic effects that have been noted with its use. For example, it is thought that the immediate analgesic effects of acupuncture may be dependent on neural (nerve) innervation. Acupuncture has also been shown to induce the release of endogenous opioids in various parts of the brain. Local tissue effects, including release of adenosine at the site of needle stimulation, have also been observed, as have increases in local blood flow. Other modes of action have been reported, including local and myofascial trigger point needling effects, segmental pain effects, extrasegmental pain effects, and central regulatory effects.