Trigger points are focal areas of spasm and inflammation in skeletal muscle. The rhomboid and trapezius back muscles, located in the upper back and shoulder areas, are a common site of trigger points. In addition to the upper spine, trigger points can also occur in the low back or less commonly in the extremities.
Often there is a palpable nodule in the muscle where the trigger point is located. The area is tender, and frequently when pushed, pain radiates from the trigger point itself to an area around the trigger point. Trigger points commonly accompany chronic musculoskeletal disorders such as fibromyalgia, myofascial pain syndrome, neck pain, and low back pain. They may also occur with tension headache and temporomandibular pain. Acute trauma or repetitive minor injury can lead to the development of trigger points.
A trigger point injection (TPI) is an injection that is given directly into the trigger point for pain management. The injection may be an anesthetic such as lidocaine (Xylocaine) or bupivicaine (Marcaine). Sometimes, a needle alone is inserted into the trigger point, and no medication is injected. This may be helpful and is referred to as “dry needling.” With the injection, the trigger point is made inactive and the pain is relieved.