A trigger point is a tight, irritable knot in a muscle that hurts when pressed and often refers pain somewhere else. A trigger point in the upper back can produce a headache. One in the hip can send pain down the thigh in a way that convincingly mimics sciatica.
A trigger point injection places a small amount of medication directly into that knot to release it.
What it treats
Trigger point injections are used for myofascial pain, which is pain originating in muscle and the connective tissue around it. Common locations are the neck and shoulders, the upper back between the shoulder blades, the lower back, and the muscles of the hip and buttock.
They are often useful for tension type headaches driven by neck and shoulder muscle tightness, for the muscle component of TMJ and jaw pain, where the chewing muscles develop trigger points, and for muscle pain that has developed secondary to a spine problem.
Why muscle pain gets missed
Myofascial pain is frequently overlooked, because imaging does not show it. An MRI of a painful back with significant trigger points can look unremarkable, and patients are sometimes told nothing is wrong.
Something is wrong. It simply does not show up on a scan. Finding trigger points takes a physical examination, hands on the muscle, and knowing what to feel for.
How the procedure works
The trigger point is located by examination, then the injection is performed under image guidance, using live X-ray or ultrasound. Many practices perform trigger point injections by feel alone. Guiding the needle means the medication reaches the knot rather than the tissue near it.
You may feel a brief twitch as the muscle responds, which is a good sign the needle is in the right place. Medication, usually a local anesthetic and sometimes a small amount of steroid, is then injected.
Several trigger points can be treated in the same visit. The appointment usually takes under thirty minutes.
What to expect afterward
Expect the treated muscle to feel sore for a day or two, the way it would after an unusually hard workout. Heat and gentle stretching help.
Many people notice improved range of motion fairly quickly. Relief varies considerably, from days to much longer, depending on what caused the trigger points in the first place.
That last point matters. Trigger points usually form for a reason, whether posture, an underlying spine problem, or how you use that muscle at work. Injections that are not paired with addressing the cause tend to be a temporary fix. We will talk about the cause, not just the knot.