Despite the fact that an estimated 44 millions Americans suffer from this disease¹. Chronic Myofascial Pain (CMP) is arguably one of the better kept secrets in the medical field. This makes it difficult for medical professionals to distinguish between CMP and other forms of soft-tissue pain, such as Fibromyalgia, arthritis, etc. Also unfortunate is that training in manual palpation skills and the practical experience needed to accurately diagnose CMP are simply not available in many medical schools.

Acute low back pain has many causes. Some are potentially serious, such as cancer metastases, massive disk herniations, etc. However the most common cause of acute back pain is so-called lumbosacral strain. In 95% of cases this resolves within three months. In those cases that do not resolve the development of a chronic low back pain syndrome is usually accompanied by the finding of active myofascial trigger points. The most commonly involve muscle group is the quadratus lumborum; pain emanating from trigger points in these muscles is felt fin the low back with occasional radiation in a sciatic distribution or into the testicles².

Trigger points involving the iliopsoas are also a common cause of chronic low back pain. The typical distribution of iliopsoas pain is a vertical band in the low back region and the upper portion of the anterior thigh. Trigger points at the origin of the gluteus medius from the iliac crest are common cause for low back pain in the sacral and buttock with a referral pattern to the outer hip region.

Latent trigger points are universal finding in many of the muscles of the posterior neck and upper back. Active trigger points commonly involve the upper portion of the trapeziums and levator scapula. Upper trapeziums trigger points referred pain to the back of the neck and not uncommonly to the angle of jaw. Levator scapula trigger points cause pain at the angle of the neck and shoulder; this pain is often described as lancinating, especially on active use of this muscle.

As many of the muscles in this area have an important postural function they are commonly activated in office workers and developmental problems causing spinal mal-alignment (e.g. short leg syndrome, hemipelvis and scoliosis). As the upper trapeziums and levator scapulae act synergistically with several other muscles in elevation and fixation of the scapula it is common for a single trigger point in this region to initiating a spread of satellite trigger points through adjacent muscles which are part of the same functional unit.

Pain arising from disorders of the hip joint is felt in the groin and the lower medial aspect of the anterior thigh. This distribution is uncommon in myofascial pain syndromes except for iliopsoas pain. The great majority of patients complain of hip pain in fact localize their pain to the outer aspect of the hip. In some patients this is due to a trochanteric bursitis, but in the majority of cases it is related to myofascial trigger points in the adjacent muscles. By far the commonest trigger points giving rise to outer hip pain are those in the attachments of the gluteus medius and minimus muscles into the greater trochanter.

The pelvic floor musculature is a common sight for myofascial trigger points. There is increasing recognition by gynecologists and urologists that pain syndromes described in terms of prostatitis, coccydnia, vulvodynia and endometriosis are often accompanied by active myofascial trigger points.

Active myofascial trigger points in the muscles of the shoulder neck and face are a common source of headaches³. In many instances the headache has the features of so-called tension headache, but there is increasing acceptance that myofascial trigger points may initiate classical migraine headaches or be part of a mixed tension/migraine headache complex.

For instance sterno-cleido mastoid trigger points refer pain to the anterior face and supraorbital area. Upper trapeziums trigger points refer pain to the vertex forehead and temple. Trigger points in the deep cervical muscles of the neck may cause post occipital and retro-orbital pain.

There is a complex interrelationship between temporomandibular joint dysfunction (TMJ) and myofascial trigger points (MTP's)⁴. Common trigger points involved in jaw pain syndromes are the massetters, pterygoids, upper trapeziums and upper sterno-cleido mastoid.

The muscles attached to the scapula are common sites for trigger points that can cause upper limb pain⁵. These included the subscapularis, infraspinatus, teres major and serratus anterior. It is not uncommon for trigger points in these locations to refer pain two the wrist hand and fingers. Extension flexion injuries to the neck often activate a trigger point in the pectoralis minor with a radiating pain or down the ulnar side of the arm and into the little finger. Myofascial pain syndromes of the upper limb are often misdiagnosed as frozen shoulder, cervical radiculopathy or thoracic outlet syndrome.

Trigger points in the tensor fascia lata and ilio tibial band may be responsible for lateral thigh pain and lateral knee pain respectively. Anterior knee pain may result from trigger points in various components of the quadriceps musculature. Posterior knee pain can result from trigger points in the hamstring muscles and popliteus. Trigger points in the anterior tibialis and the peroneus longus muscles may cause pain in the anterior leg and lateral ankle respectively. Myofascial pain syndromes involving these muscles are often associated with ankle injuries or an excessively pronated foot. Sciatica pain may be mimicked by a trigger point in the posterior portion of the gluteus minimus muscle.

Disorders affecting intrathoracic and intra-abdominal organs are some of the commonest problems encountered in internal medicine. For instance, anterior chest pain is a frequent cause for the emergency room admissions, but in the majority of patients a myocardial infarction is not found. In some cases the chest pain is caused by trigger points in the anterior chest wall muscles⁶.

Pectoralis major trigger points cause ipsilateral anterior chest pain with radiation down the ulnar side of the arm - thus mimicking cardiac ischemic pain. A trigger point in the sternalis muscle typically causes a deep substernal aching sensation. Trigger points at the upper and lower insertions of the rectus abdominus muscles may mimic the discomfort of gall bladder and bladder infections respectively. It is important to note that myofascial trigger points may accompany disorders of intrathoracic and intra-abdominal viscera, and thus a diagnosis of an isolated myofascial cause for symptoms should never be made without an appropriate work up.