When using Medical Acupuncture in the treatment of musculoskeletal pain, I find myself in the main selecting either segmental points or trigger points if present, sometimes both.
Segmental points are basically those where tissue, preferably muscle, which shares the same segmental innervation as the structure likely to be responsible for nociceptive input, is stimulated. Trigger points must meet with the relevant diagnostic criteria and when using Medical Acupuncture to deactivate may be referred to as dry needling. These terms are often used interchangeably however, at least in Europe.
One of the conditions for which I find segmental Acupuncture particularly useful is that of knee osteoarthrosis and associated pain symptoms. The evidence would generally support using more local to the knee joint (White, 2007) and I would select points within muscles which act on the knee joint as well as sharing the same segental innervation. That said, so called sham Acupuncture can also be beneficial in providing pain relief and often extra-segmental points, those outside the segment, are used to augment the effects of segmental points.