Thoracic Outlet Syndrome

by Erik Dalton Ph.D.
founder of Freedom From Pain Institute

Erik Dalton Massage Therapy Home Study Newsletter

Was great seeing so many of you at the AMTA National Convention a couple weeks ago. We apologize to all who tried to enroll in the Saturday Myoskeletal Alignment workshop but it was pretty cramped with 141 participants. Want to thank my wonderful teaching assistants (Kim Miller, Paul Kelly, Geoffrey Bishop, Nick Cress, Danny Christie and Sandi Brinlee) for keeping the 8-hour seminar running so smoothly.

Many of you were inquiring about details for our upcoming 3-Day (24 CE) Denver and Baltimore workshops. To be clear, we always dedicate one day each to Neck and Low Back work since they are two of the most common complaints seen in clinic. Typically, Sunday is reserved for addressing complex pain-generating dysfunctions in either the upper or lower extremities.

However, one extremely important condition included, but not always mentioned in the Shoulder, Arm & Hand section, is our newsletter topic of the day…

thoracic
Humans are not well adapted as beasts of burden and heavy loads hung from the shoulders and arms can really stress shoulder girdle support structures. Since the weight of the scapula and arm takes its support from the clavicle and its component ligaments and muscles, occupations requiring repetitive overhead arm movements can produce symptoms of compression. Electricians, painters, dancers and competitive athletes such as swimmers and pitchers may develop hyperabduction syndrome due to excessive frictioning of neurovascular structures in the shoulder and brachial region. The generic term ‘thoracic outlet syndrome’ (TOS) is often used to describe a variety of symptoms associated with this and other shoulder impingement syndromes.

upper crossTOS is a controversial topic in the literature; many proponents support the existence of the condition, but some strongly vocal opponents doubt the validity of TOS as a medical entity. The primary controversy seems to center around the lack of universally reliable assessments and the confusion with multiple types and clinical presentations.

Fortunately, new MRI scanning technology available in many major USA hospitals is now able to accurately identify and localize TOS and other nerve entrapment syndromes. Researchers at Cedars-Sinai Medical Center, the University of California, Los Angeles, and the Institute for Nerve Medicine in Los Angeles, have developed a new nerve imaging technology called ‘Magnetic Resonance Neurography’ which has proven extremely effective in implicating sites of peripheral nerve damage.1

TOS involves compression, injury, or irritation to neurovascular structures at the root of the neck, upper thoracic region, or beneath the pectoralis minor muscle. Compression syndromes at these sites are primarily neurologic and involve the brachial plexus—most often the lower trunk or medial cord. Additionally, the subclavian artery and vein may also be compromised. Cervical nerves and vessels often become trapped between fibrotic anterior and middle scalene tendons as they enter the thoracic inlet (Fig.1.anterior scalene syndrome). Prolonged scalene spasm from injury or overuse can also cause problems as they tug on the first rib pulling it up against a ‘drooping’ clavicle. When the brachial plexus gets squashed between the clavicle and rib, a condition known as costoclavicular syndrome arises. This disorder is one of the leading causes of TOS.

Commonly seen muscle imbalance patterns such as Vladimir Janda’s upper crossed syndrome (Fig. 2) play a major role in the formation of entrapment neuropathies.

techniquetechniqueAs tight pectoral muscles roll the shoulder girdle forward on the ribcage, the clavicles drop onto the first thoracic rib causing brachial plexus compression. Anterior displacement of the humeral head (tight pecs and lats) is also an area of impingement associated with upper crossed patterns. Fortunately, many illusive TOS cases are easily corrected using structural integration techniques such as those shown in Figures 3 and 4.

Successful long-term alleviation of pain, numbness, swelling, and paresthesias associated with this troublesome disorder requires that all upper quadrant postural asymmetries (slumped shoulders, forward heads, hyperkyphosis, etc.) be corrected prior to releasing smaller ‘impinging’ muscles such as intertransversarii, scalenes, and subclavius.

Below is a summary of component syndromes which comprise thoracic outlet syndrome along with a brief description of each.

  • forceIntertransversarii fibrosis: Consisting of rounded muscular and tendinous fasciculi running from anterior and posterior tubercles of the transverse processes of two contiguous vertebrae, reflex spasm from cervical joint fixations or facet ‘spurring’ (Figure 5) causes them to tighten and squeeze on spinal nerve roots. An often neglected site of nerve root compression, these tissues are usually easy to release using contract/relax stretching techniques shown in my Myoskeletal Volume III, Shoulder, Arm and Hand videos.
  • Anterior scalene tightness: Compression of the interscalene space between the anterior and middle scalene muscles frequently causes reflex spasm. This condition is primarily due to long-term nerve root irritation from spondylosis
    or facet joint inflammation.
  • Costoclavicular approximation: Postural deficiencies and carrying heavy objects results in neurovascular compression in the space between the clavicle, first rib and musculoligamentous
    structures.
  • Pectoralis minor tightness: Repetitive movements of the arms above the head (shoulder elevation and hyperabduction) frictions and irritates the nerve plexus between the pectoralis minor tendon under the coracoid process.

Simply stated, ‘double crush’ means that if any given nerve is subjected to a proximal compressive neuropathy then it is more prone to the development of a second or ‘double’ distal neuropathy. Double crush syndrome was first described in the medical journal ‘Lancet’ in 1973. The term refers to a diagnosis of a compressed or trapped nerve in one area (e.g. the neck or thoracic outlet), with a second entrapment in another location (e.g. the carpal tunnel or Guyon’s tunnel in the elbow), with both entrapments contributing to symptoms.

Some researchers suggest that the presence of an undiagnosed entrapment in another location may explain why some people still experience symptoms after carpal tunnel surgery. This has led manual therapists to question if examination of the hand alone is sufficient when dealing with syndromes such as carpal tunnel. Therapeutic outcomes are more successful when the nerves along the entire length of the arm are examined beginning proximally from the cervicothoracic spine down through the wrist and hand.

Summary

Because the shoulder and neck area consist of very complex body parts with muscles and connective tissues going in all possible directions, therapists must focus intent on correcting postural strain patterns prior to ‘chasing the pain’. A few commonly applied provocation tests for assessing TOS such as the Adson maneuver (scalenes), ‘Hands-up’ (pec minor), Allen (radial pulse) and the Elevation maneuver for costoclavicular canal impingement may be used. These tests may or may not momentarily reproduce symptoms but are sometimes helpful in ruling out other causes which may produce similar symptoms.

Due to the overlapping of symptoms, it’s often difficult to make a definitive assessment using provocation tests. Fortunately, advancements in nerve imagery using Magnetic Resonance Neurography are providing more accurate monitoring of exact sites of peripheral nerve damage. These tests, accompanied by thorough history and postural evaluations are extremely helpful in preventing the formation of adhesions that trap and irritate the nerve bundle that brings sensation to the arm and hand.

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References

  1. Filler A., Haynes J, Jordan S, Prager J, Villablanca J, Farahani K, McBride D, Tsuruda J, Morisoli B, Batzdorf U, Johnson J, Journal of Neurosurgery, 2005, pp.99-115