Myofascial trigger points

Myofascial pain syndrome is a term used to describe pain and maybe concomitant visceral dysfunction due to the presence of a "Tight fascial-muscular band" within a muscle or muscle group that act like a pain "Trigger point" causing referred pain in another area. The area affected by this trigger point will show pain, decreased range of movement, muscular weakness, and often accompanied autonomic phenomenon

A myofascial trigger point pathophysiology can be summarized as the following:

1. Restricted movement: taut muscle bands lead to shortening of the muscles, which in turn leads to reduced mobility and articular dysfunction. Depending on the muscle involved, different symptoms can arise

2. Vascular perfusion abnormality: if the taut bands compress the intra- or extra-muscular blood vessels, this leads to tissues ischemia, formation of edema, and trophic/metabolic changes

3. Neuromuscular entrapment: fascia contains many nerve fibers embedded within fascial tunnels (e.g., medial superior cluneal nerve tunnel). A tense muscle and fascial fibers can exert pressure over the surrounding nerve fibers resulting in entrapment syndromes and variety of neurological symptoms  

4. Irritation of deep propioceptive and nociceptive nerve endings: connective tissue dysfunction alters the flow of impulses which come from the receptors which lie in the connective tissue of the muscle.

5. Metabolic abnormalities: fascial tension can disturb circulation in the interstitium disturbing the cellular environment

6. Breathing disorder: myofascial tension affects posture as well as abdominal and intra-thoracic pressure

Examples of symptomatology of myofascial trigger points:

Breast pain (Mastalgia): pectoralis major and minor muscles

Headache: temporalis, pterygoid, upper trapezius, and sternocleidomastoid muscles

Lower back / SJ joint pain: pyramidalis, gluteus maximum, medius, and minimus muscles

Inguinal pain: quadratus lumborum, Iliopsoas, and abdominal oblique muscles

Pain during sitting: pyramidalis and obturator internus muscles

Vulvar pain (Vulvodynia): external anal sphincter

Testicular pain (Orchialgia): abdominal oblique, gluteus maximum, medius, and minimus muscles

Penile pain: levator ani, bulbospongiosus, ischiospongiosus, and rectus abdominis muscles

Prostate pain (Prostatodynia): levator ani muscle

Perianal pain: levator ani muscle

Rectal pain (Proctodynia): levator ani, coccygeus, and external anal sphincter muscles

Sensation of a ball in the rectum: levator ani and obturator internus muscles

 

Selected references

1. Finando S et al. Fascia and the mechanism of acupuncture. Journal of Bodywork & Movement Therapies 2011; 15: 168-176

2. Raj PP et al. Myofascial pain syndrome and its treatment in low back pain. Semin Pain Med 2004; 2:167-174

3. Itza F et al. Myofascial pain syndrome in the pelvic floor: A common urological condition. Actas Urol Esp 2010; 34(4):318–326

4. Montenegro MLLS et al. Abdominal myofascial pain syndrome must be considered in the differential diagnosis of chronic pelvic pain. European Journal of Obstetrics & Gynecology and Reproductive Biology 2009; 147: 21–24

5. Barnes MF. The basic science of myofascial release: morphologic change in connective tissue. Journal of Bodywork and Movement Therapies 1997; 1(4), 231-238