Trigger Points: What are They and How Do They Contribute to Pain?

May 6, 2022 - Written By: Maria Arini Lopez, PT, DPT

Have you ever had a massage where the therapist found an especially tender area in the muscle that felt like a knot? Perhaps you have found these muscle knots yourself trying to self-massage painful areas away.

These tender, localized knots in the muscle tissue are called trigger points and they can contribute to chronic pain and muscle dysfunction. They shorten muscle fibers, restricting the normal muscle contraction and limiting range of motion. Basically, trigger points decrease muscle strength and mobility.

Trigger points also restrict blood flow and nutrition to the muscle tissue. Because blood is naturally slightly basic, this lack of blood flow creates more acidic environment. Lactic acid also builds up in the muscle because it cannot be carried away by blood flow.

The body has specialized sensory nerves that monitor specific conditions within the body such as temperature, pressure, stretch, and chemical changes such as acid-base balance. The more acidic environment within the region of a trigger point is perceived as abnormal, so these nerves (called nociceptors) send signals to the brain indicating that the body is in danger. In response to these signals, the body naturally sends inflammatory chemicals to the abnormal region to fix the problem. Unfortunately, these inflammatory chemicals cause pain.

Pain may spread to other areas which are remote from the location of the trigger point. This is called referred pain. Referred pain results due to how pain signals are processed within the brain and spinal cord, often affecting a wider area. An example of referred pain is pain which accompanies a heart attack. A person may feel pain or pressure directly on the left side of the chest, or the pain may travel to the left shoulder, left arm, neck, or jaw.

Healthcare providers who specialize in trigger point release treatments are trained to recognize referred pain patterns and can treat the trigger points causing widespread pain.

Why Do Trigger Points Form?

Trigger points occur in muscles that are injured or overused due to repetitive movements or overtraining. Poor posture which forces the muscles to work at disadvantaged lengths also may contribute to trigger point development. Emotional stress and anxiety may cause trigger points because individuals who are stressed or anxious are more likely to tense up their muscles in response.

Overworked muscles trying to stabilize joints that are hypermobile may also form these trigger points because of the increased workload of the muscles to protect the joints.

While mostly everyone has trigger points, not all are symptomatic. Trigger points that are not symptomatic are called latent trigger points. They may restrict range of motion, but they do not cause pain unless aggravated. Trigger points that cause pain are called active trigger points. It is possible that these active trigger points can progress into more chronic, debilitating conditions such as myofascial pain syndrome and fibromyalgia. When the pain worsens, it may cause problems sleeping because pressure on these trigger points can aggravate the pain.

How Can Trigger Points Be Treated?

There are several treatments for trigger points, including therapeutic massages, trigger point dry needling, and trigger point injections.

Massage therapists, physical therapists, and trained body workers can release trigger points using moderate amounts of direct compression on the trigger point with their hands, elbows, or other tools for a certain length of time. Following this treatment, blood flow to the muscle tissue improves and pain levels decrease. The therapist and the person being treated might feel the muscle relax and lengthen in response to the treatment.

Trigger point dry needling is an invasive treatment using very small, solid, thin needles to directly target and release the trigger points. This type of treatment might be preferable because only a small area of muscle tissue is affected compared with compression. Because direct compression uses a larger tool (the therapist's hand, fingers, elbow, or any other tools they choose to use) to target the trigger point, this covers a larger area which may aggravate the soft tissues surrounding the trigger point or may be too painful to tolerate if the trigger point is already flared up. Trigger point dry needling may be an alternative treatment that works better for some people.

During trigger point dry needling sessions, the healthcare provider looks for an involuntary, localized, twitch response of the muscle to confirm that the trigger point was released. The muscle will relax and lengthen, instantly increasing range of motion and muscle strength. Often, people will experience immediate relief from the pain caused by that trigger point. Following trigger point dry needling, people may experience muscle soreness and stiffness, so gentle stretching and movement to increase blood flow to the area is important to maintain the newly achieved range of motion of the muscle.

Trigger point injections are another treatment directly targeting these trigger points. Unlike trigger point dry needling, this treatment uses hollow needles to allow injection of a fluid medication into the trigger point. This injection includes a local anesthetic like lidocaine to relieve pain and may contain an anti-inflammatory like a corticosteroid.

Some trigger point injections may contain Botox, a paralyzing toxin obtained from a strain of bacteria called clostridium botulinum. Botox helps to relax the muscles for long periods of time, usually between 3 to 6 months. This may be helpful for those who experience headaches caused by trigger point referrals. Individuals with hypermobility of the neck should avoid Botox in stabilizing muscles because Botox may increase neck instability, resulting in increased pain, tissue damage, and possibly serious injury. For people with allergies to such medications, trigger point dry needling may be an alternative treatment to consider.

Which Treatment Should Be Tried First?

May 29, 2022 - Written By: Maria Arini Lopez, PT, DPT chronic pain from trigger points in the muscles. Everyone responds differently, so trying out different treatment options under the guidance of your doctor might be helpful to figure out which one is best for you persona

References and Resources

1. Trigger Point Injection Side Effects & Medications. Ramos Center. Accessed April 27, 2022.

2. Trigger Point Injection (TPI) for Pain Management. WebMD. Accessed April 27, 2022.

3. Myofascial pain syndrome - Symptoms and causes. Mayo Clinic. Accessed April 27, 2022.

4. Myofascial Pain: Treatment, Symptoms, Causes, and More. Healthline. Published August 22, 2017. Accessed April 27, 2022.

5. Rivner MH. The neurophysiology of myofascial pain syndrome. Curr Pain Headache Rep. 2001;5(5):432-440. doi:10.1007/s11916-001-0054-6

6. Moraska AF, Hickner RC, Kohrt WM, Brewer A. Changes in blood flow and cellular metabolism at a myofascial trigger point with trigger point release (ischemic compression): a proof-of-principle pilot study. Arch Phys Med Rehabil. 2013;94(1):196-200. doi:10.1016/j.apmr.2012.08.216

7. Pain Principles - Neuroscience Online: An Electronic Textbook for the Neurosciences. Section 2, Chapter 6. Department of Neurobiology and Anatomy - The University of Texas Medical School at Houston. Accessed April 27, 2022.

8. Ischemic Compression - an overview. ScienceDirect Topics. Accessed April 27, 2022.

9. Referred Pain. Physiopedia. Accessed April 27, 2022.

10. Trigger Point Injections with Botox (Botulinum Toxin A) for the Treatment of Neck Pain. London Pain Clinic. Published May 12, 2016. Accessed April 27, 2022.

11. Increased Risks of Botulinum Toxin Injection in Patients with Hypermobility Ehlers Danlos Syndrome: A Case Series.MDS Abstracts. Accessed April 27, 2022.

Maria Arini Lopez, PT, DPT

Maria Arini Lopez, PT, DPT, CSCS, CIMT, CMTPT is a freelance medical writer and Doctor of Physical Therapy from Maryland. She has expertise in the therapeutic areas of orthopedics, neurology, chronic pain, gastrointestinal dysfunctions, and rare diseases, especially Ehlers Danlos Syndrome.