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by Stahl RJ

Trigger Point Injection

(Injection, Trigger Point)


A trigger point is a painful area in a muscle. It may feel like there is “knot” in the muscle or an area of tightness. When pressure is applied to the trigger point, the pain spreads out to other areas of the body.
A trigger point injection is a shot that is given in this painful spot.
Thigh Muscles
Posterior Thigh Muscles
If you have a trigger point in the thigh muscle, the doctor can give an injection to relieve pain.
Copyright © Nucleus Medical Media, Inc.

Reasons for the Procedure

Trigger point injections are given to reduce pain and increase physical functioning so that you can participate in a physical therapy program.

Possible Complications

Potential problems are rare. But, all procedures have some risk. Your doctor will review potential problems, like:
  • Tenderness, bruising, or bleeding at the injection site
  • Infection
  • Lightheadedness
  • Allergic reaction to the local anesthetic or medicine
  • The need for other treatments if this injection is not effective
  • Damage to organs, such as the lung (rare)
Smoking may increase the risk of complications.
You should not have this injection if you:
  • Have allergies to the local anesthetic or medications being used
  • Have a current infection
  • Have a bleeding disorder
  • Are pregnant

What to Expect

Prior to the Procedure

Before the procedure you may need:
  • A physical exam
  • Imaging tests to evaluate the spinal structures with x-rays or an MRI scan
  • To discuss allergies that you may have to the anesthetic, pain medication, or latex
In addition, talk to your doctor about your medications. You may have to stop taking some medications up to one week or more before the procedure.
Depending on where your trigger point is, you may need someone to drive you home after the procedure.


You will typically remain awake during the procedure. A local anesthetic may be used to numb the area where the injection will be given.

Description of the Procedure

First, the skin around the painful area will be cleansed with an antiseptic. Next, the doctor will locate the trigger point. This may be done by feeling for the painful area with his fingers. Once the trigger point in found, a thin needle containing medicine will be injected. The injection may contain a long-acting pain reliever, a water solution, or a corticosteroid to reduce inflammation. Botulinum toxin is also sometimes used for trigger point injections associated with muscle contraction. Sometimes the doctor will simply put the needle into the trigger point and not inject any medicine. This is all done to break the pain cycle at the trigger point. If you have more than one trigger point, you may need several injections.
Some doctors may use needle-guided electromyography (EMG) to locate the trigger point. With this approach, a needle will send information to a monitor, which will allow the doctor to make sure he has located the right spot.

How Long Will It Take?

The injection takes a few minutes.

Will It Hurt?

When the doctor feels for the trigger point, you will have discomfort. You will also feel a pinching sensation when the needle goes through your skin. You may have pain, which should not last long.

Post Procedure Care

At the Care Center
The hospital staff will apply pressure to the injection site and place a bandage. You will be observed for a short time to make sure you do not have any poor reactions to the injection. Then, you will be able to go home or return to work.
At Home 
To reduce soreness, apply ice or a cold pack to the affected area to ease discomfort. Your doctor may advise pain medications. You may need to meet with your physical therapist soon after the injection to take advantage of the pain relief in your muscles.
You may have pain relief for weeks or even months. In some cases, you may need to have more than one trigger point injection. Talk to your doctor about how often you will need this treatment.

Call Your Doctor

It is important to monitor your recovery. Alert your doctor to any problems. If any of the following occur, call your doctor:
  • Signs of infection, including fever and chills
  • Redness, swelling, increasing pain, bleeding, or discharge from the injection site
  • Numbness, tingling, pain, or weakness
  • Any new or unexplained symptoms


American Chronic Pain Association
Ortho Info—American Academy of Orthopaedic Surgeons


The Arthritis Society
Health Canada


Alvarez D, Rockwell P. Trigger points: diagnosis and management. Am Fam Physician. 2002;65(4):653-661.
Trigger point injections. Integrative Pain Center of Arizona website. Available at: http://www.ipcaz.org/?s=trigger+point+injections. Accessed March 3, 2011.
Trigger point injections. Memorial Sloan-Kettering Cancer Center website. Available at: http://www.mskcc.org/cancer-care/patient-education/resources/trigger-point-injections. Accessed March 3, 2011.
Trigger point injections. University of Wisconsin Hospital website. Available at: http://www.uwhealth.org/healthfacts/B%5FEXTRANET%5FHEALTH%5FINFORMATION-FlexMember-Show%5FPublic%5FHFFY%5F1126652225741.html. Updated June 21, 2010. Accessed March 3, 2011.
Trigger point injection therapy. Fibromyalgia Symptoms website. Available at: http://www.fibromyalgia-symptoms.org/fibromyalgia%5Finjections.html. Accessed March 3, 2011.
6/6/2011 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Mills E, Eyawo O, et al. Smoking cessation reduces postoperative complications: A systematic review and meta-analysis. Am J Med. 2011;124(2):144-154.e8.

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