We've known since the early 2000's how acupuncture works via the nervous system: a review from 2008.
While a bit outdated and lacking up-to-date evidence of the anatomical basis for acupuncture, this wonderful summary of the physiological basis for acupuncture still holds a solid review of the understanding of the impacts and mechanisms of acupuncture from a biomedical perspective: "Several conclusions can be made based on the above neurophysiologic studies. First, afferent nociceptive pathways are essential for acupuncture analgesia. Second, acupuncture analgesia is mediate