Trigger point injections involve inserting a needle into a tight, painful knot in a muscle, then either injecting a small amount of local anesthetic or simply using the needle itself to release the tension. The procedure takes just a few minutes per trigger point and is performed in an office setting without sedation. While the core technique is straightforward, doing it well depends on accurately finding the trigger point, stabilizing it, and using proper needling motion to release the contracted muscle fibers.
Finding the Trigger Point
The entire procedure hinges on correctly identifying the trigger point before the needle goes in. A trigger point is a hyperirritable spot within a taut band of skeletal muscle, felt as a small, firm nodule under the fingers. When you press on it, the patient typically reports sharp tenderness at the spot and often pain that radiates to a predictable area nearby. That referred pain pattern is one of the most reliable confirmation signs.
To locate a trigger point, palpate the muscle using flat fingers or a pincer grip, sliding across the muscle fibers rather than along them. You’re feeling for a ropy, taut band first, then zeroing in on the most tender nodule within that band. Pressing firmly on the nodule may produce a “jump sign,” where the patient flinches involuntarily, and sometimes a visible local twitch response in the muscle. Research on diagnostic accuracy shows that finding a taut band containing a hypersensitive spot is the most decisive criterion, but the diagnosis is strongest when that finding combines with referred pain or a local twitch response.
Some clinicians mark each identified trigger point with a skin marker or the retracted tip of a pen before starting, which prevents losing the spot once the procedure begins.
Equipment and Setup
The supply list is minimal. You need a syringe (5 or 10 mL), the appropriate needle, alcohol pads or chlorhexidine for skin prep, and your chosen injectate if you’re doing a wet needling technique.
Needle selection depends on muscle depth. According to the American Academy of Family Physicians, a 22-gauge, 1.5-inch needle works for most superficial muscles like the upper trapezius. Thicker muscles such as the gluteus maximus or the paraspinal muscles typically require a 21-gauge, 2.0-inch needle. The deepest muscles, including the gluteus minimus and quadratus lumborum, call for a 21-gauge, 2.5-inch needle.
Position the patient so the target muscle is accessible and relaxed. For upper trapezius or neck trigger points, the patient is usually seated. For low back or gluteal trigger points, they lie prone or on their side. A topical anesthetic spray can be applied before starting if desired.
The Injection Technique Step by Step
After cleansing the skin and allowing it to dry, stabilize the trigger point by pinching it between the index finger and thumb of your non-dominant hand. This serves two purposes: it anchors the nodule so it can’t slide away from the needle, and it provides tactile feedback throughout the procedure.
With your dominant hand, insert the needle at roughly a 30-degree angle into the trigger point. Once the needle is in the muscle, begin a rhythmic pattern of advancing and partially retracting the needle without pulling it completely out of the tissue. Redirect the needle in multiple directions with each pass, essentially fanning through the trigger point. You’ll often feel a crunching or pulling sensation through the needle as it passes through the contracted fibers. This sensation typically fades as the muscle releases.
The goal is to elicit and then exhaust the local twitch response. Each twitch represents a small group of taut muscle fibers firing and then releasing. Continue the needling motion until the twitching stops or the tissue feels noticeably softer and more relaxed under your fingers.
If you’re performing dry needling, the procedure is complete at this point. If you’re injecting medication, aspirate first to confirm the needle tip isn’t in a blood vessel, then inject 0.2 to 1 mL of solution into the trigger point. You can use a direct injection or continue the fanning motion while injecting small amounts at each pass. For multiple trigger points, repeat the entire process at each site.
What to Inject (or Whether to Inject at All)
The most common injectate is dilute lidocaine. Research suggests the optimal concentration is lower than many clinicians assume. Studies comparing various dilutions found that lidocaine diluted to 0.2% to 0.25% produced less injection pain and better results than standard 1% lidocaine. This is typically achieved by mixing 1% lidocaine with sterile water at a 1:3 ratio.
Dry needling, where no substance is injected, is a legitimate alternative. A systematic review of 26 randomized trials found that dry needling produces outcomes similar to most injection types for pain and disability. The one exception: local anesthetic injection appears more effective at reducing pain in the short term. Over the long term, the differences largely wash out. Dry needling actually showed better long-term outcomes than steroid injections, and results comparable to platelet-rich plasma. Adverse event rates were similar between dry and wet needling approaches.
Professional guidelines recommend against routinely using botulinum toxin for myofascial trigger points. The choice between dry needling and local anesthetic injection often comes down to patient preference, since the anesthetic provides more immediate comfort during and after the procedure.
What the Patient Feels
The initial needle stick feels like a brief, sharp pinch. Once the needle enters the trigger point, patients commonly feel a deep ache or cramping sensation, especially when the needle elicits a twitch response. Some describe it as a “good hurt,” similar to pressing hard on a sore spot. The twitching itself can feel strange but is actually a sign the procedure is working.
After the injection, the area often feels sore for a day or two, similar to post-exercise muscle soreness. This is normal. Applying ice or gentle heat to the area and doing light stretching of the treated muscle can help. Most people return to normal activities the same day, though it’s reasonable to avoid intense exercise involving the treated muscle for 24 to 48 hours.
Safety Considerations
The most serious risk is pneumothorax, a punctured lung, which is possible when injecting trigger points in the upper back, neck, or chest wall where the needle could reach the pleura. Angling the needle away from the rib cage and using the pincer grip to lift the muscle away from underlying structures reduces this risk. A 2024 guideline from the American Society of Regional Anesthesia recommends considering ultrasound guidance when injecting near high-risk tissues, including areas close to nerves, blood vessels, or the lungs, and for trigger points located in deeper muscles.
Other potential complications include bleeding or bruising at the injection site, infection (minimized by proper skin prep), and, with local anesthetic, the rare possibility of an allergic reaction or systemic toxicity if too much anesthetic is used across multiple sites. Aspiration before injecting is a critical safety step to avoid injecting anesthetic directly into a blood vessel.
How Often to Repeat Injections
Trigger point injections work best as part of a broader approach that includes stretching, posture correction, and addressing whatever is perpetuating the muscle tension. The injection breaks the pain cycle, but if the underlying cause persists, trigger points tend to recur.
Guidelines from the American College of Occupational and Environmental Medicine recommend waiting at least 3 to 4 weeks between injection sessions. The American Society of Interventional Pain Physicians suggests at least one to two weeks between sessions during the initial phase, with a maximum of 4 sessions per year. Both organizations agree that if a patient shows no improvement after two sessions, repeated injections are unlikely to help and a different treatment approach should be considered.
Many patients experience significant relief after just one or two sessions, particularly when they follow up with consistent stretching and physical therapy targeting the affected muscle group.