Mississauga Chiropractor Presents: Thoracic Outlet Syndrome – TOS

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Categories: Lecture Series

Here’s another blog from a Mississauga Chiropractor…


Thoracic Outlet Syndrome is the general term for a condition resulting in the compression of neurovascular structures (nerves of the brachial plexus, subclavian artery & vein) at the thoracic outlet, causing symptoms in the upper extremities, neck and chest.  When it is present, the C8-T1 spinal levels are the most commonly involved.



a)      Neurologic Type (90-97%) – Females > Males (3.5:1), ages 20-35 years old

b)      Venous Type (3-10%) – Males > Females, ages 20-35 years old


Potential Causes:

a)      Prior shoulder/lower cervical trauma or repetitive activity (e.g. typing/mousing on computer)

b)      Upper thoracic neurovascular bundle compression

c)      Cervical rib or fibrous band connecting the cervical rib to the 1st rib

  • Approximately 1% of the population may have cervical ribs

d)      Elongated C7 transverse process

e)      Pancoast’s tumor (upper lung)

f)        Atherosclerotic plaques with vessels

g)      Tight subclavian muscle, tight pectoralis minor, tight scalenes muscles

h)      Callous bond formation from fractured clavicle or first rib


Risk Factors:

a)      Postural abnormalities (e.g. rounded shoulders, scoliosis), awkward sleeping positions (abducted shoulders)

b)      BodyBuilding, with increased muscular bulk in the thoracic outlet area

c)      Obesity, large breast tissue



a)      Usually unilateral numbness, tingling or paresthesia of upper limb & shoulder

b)      Constant ache with paresthesisa, pain down medial aspect of the arm & hand (very common)


Specific Characteristics of Neurologic TOS (most common)

a)      Pain, usually on the medial aspect of the arm, forearm, ring finger and small digits

b)      Paresthesias, often at night; patient may awaken with pain or numbness

c)      Loss of dexterity, cold intolerance, occipital headache

d)      Raynaud phenomenon – hand coldness, and colour changes due to an overactive sympathetic nervous system

e)      Prior history of neck trauma (motor vehicle accident, repetitive stress activity at work)


Specific Characteristics of Venous TOS

a)      Pain (usually in younger men, preceded by vigorous activity in the arms)

b)      Swelling of the arm, cyanosis

c)      Paresthesias in the fingers and hand


Specific Characteristics of Arterial TOS

a)      Pain, pallor, coldness & paresthesias

b)      Usually with young adults with a history of vigorous arm activity



a)      Anterior head carriage with hypertrophic SCM & scalenes

b)      Tenderness over the scalenes, brachial plexus & lower cercial spine or above clavicle

c)      Hypertonic muscles or trigger points in the scalenes or pectoralis minor


Neurological Exam

a)      Muscle weakness (shoulder abduction, grip strength)

b)      Decreased grip strength



a)      Stretch & Strengthen (Maximize the thoracic outlet space by stretching and strengthening of the shoulder-elevating mechanism

  • Stretch tight & shortened scalenes, pectoralis minor & other cervical muscles
  • Strengthen the trapezius and rhomboid (e.g. shoulder shrugs, wall angels, WTYI-prone)
  • Shoulder mobilization (e.g. hand circles and standing corner pushups)
  • Postural exercises (e.g. cervical and lumbar spine extension)


b)      SMT (spinal manipulative therapy) and/or mobilizations to the upper ribs, cervical & thoracic spine to improve mobility & biomechanics


c)      Massage Therapy – ART (active release techniques) & muscle stripping of the scalenes and SCM


d)      Activity Modification:

  • Light activity level with arms & hand
  • No heavy activity for 2-3 months
  • No straining shoulder exercise programs
  • Rehabilitation for faulty posture
  • Avoid repetitive overhead activities



  • 85% of patients will improve with appropriate chiropractic care.  Osseous adjustments have been shown to be highly effective in treating TOS, especially in combination with vigorous stretching and muscle release to the scalenes and pectoralis muscles.



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