A Chinese medical technique, acupuncture has been practiced in China for more than 4,500 years. By the late 20th century it was also being used in many other parts of the world. Acupuncture is performed primarily for the relief of pain but also for curing disease and improving general health.

Acupuncture consists of inserting hair-thin needles through particular spots in the skin (acupuncture points) into neuroreceptors in underlying muscles. The needles are typically inserted ¹/₁₀ to ⁴/₁₀ inch (0.3 to 1 centimeter) deep, but some procedures require the needles to be inserted as deep as almost 10 inches (25 centimeters). The acupuncture points are then stimulated by gentle twirling or the application of heat or a weak electrical current. Acupuncture points also can be stimulated by pressure, ultrasound, and certain wavelengths of light. The practitioner frequently inserts needles at a considerable distance from the part of the body on which they are intended to act. A needle inserted into the pad of the thumb, for example, is expected to relieve pain in the abdomen. Location of the points is mastered by the use of innumerable diagrams and models.