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British Medical Books Health Issues Computerized Tomography

Definition

  • neurological & vascular symptoms & signs in the upper limbs
  • produced by compression of the lower trunk of the brachial plexus & subclavian vessels between the clavicle & the most proximal rib

Anatomy

  • both the subclavian artery and the brachial plexus traverse between the anterior & middle scaleni muscles
  • base of the triangle is the 1st rib
  • even under N circumstances these NV structures bend acutely when the arm rest at the side
  • an extra rib (cervical rib) or fibrous equivalent, anomalous scalene muscle sharpens the angle
  • in some cases, thoracic outlet syndrome will be accentuated by recurrent anterior shoulder instability, and this may be the cause of the “dead arm syndrome”

Diagnosis

History

  • anomalies are all congenital
  • yet symptoms are rare before the age of 3O
  • with declining youth, the shoulders sag, increasing the bend of the NV bundle
  • indeed drooping shoulders alone may cause the syndrome

Clinical features

  • no general symptoms or neck symptoms
  • usually a female in her 30, may complain of

Symptoms

  • pain and/or paraesthesia in the ulnar forearm & hand
    • worse after household chores or after carrying shopping
  • weakness or clumsiness
  • excessive sweating, or blueness & coldness of the fingers
  • a female, the patient is often long-necked with sloping shoulders (like a Modigliani painting)
  • if a male, he is more likely to be thick-necked and muscular

Signs

  • lump (the abnormally elevated subclavian artery) may be palpable above the clavicle
    • pulsates, tender and pressure on it may increase symptoms
  • neurological signs predominate (lower trunk C8, T1 - mostly ulnar N )
    • mild clawing of hands
    • wasting of the interosseous and hypothenar muscles
    • weakness of the intrinsics
    • reflexes are usually normal
    • sensation may be diminished in the C8 and T1 distribution
  • vascular signs are uncommon
    • may be cyanosis and increased sweating

Special tests

  • used for pulse obliteration or provoke symptoms
  • Roos test
  • pulse fades when the arm is elevated to 90 degrees and externally rotated while the neck is turned to the opposite side
  • in another the same effect is produced by pulling the arm downwards and backwards while pushing the neck away

Neck and shoulder

  • movements are normal
  • excluding a diagnosis of cervical disc disease or musculo-tendinous cuff disorder

X-ray

  • may show a 'long' neck - i.e. the first thoracic vertebra stands clear in views of the cervical spine
  • occasionally a well-formed cervical rib, but more often just an enlargement of the transverse process of C7
  • CXR to rule out pancoast tumor

Differential diagnosis

Cervical spine lesions

  • In disc prolapse or spondylosis, pain is more vaguely distributed
  • neck movements are limited
  • in tuberculosis and secondary deposits the x-ray appearance is characteristic

Carpal tunnel syndrome

  • spina bifida occulta 30-70% with isthmic, 40% with dysplastic ~
  • many cases were wrongly called cervical rib syndrome
  • even when x-rays show a rib, the symptoms may still be due to median nerve compression in the carpal tunnel
  • nocturnal pain and its distribution are characteristic

Ulnar tunnel syndrome

  • symptoms and signs are sharply confined to the distribution of the ulnar nerve
  • the neck is unaffected

Pancoast syndrome

  • apical carcinoma of the bronchus may infiltrate the structures at the root of the neck, causing pain, numbness and weakness of the hand
  • hard mass may be palpable in the neck
  • x-ray of the chest shows a characteristic opacity

Spinal cord lesions

  • syringomyelia or other spinal cord lesions may cause wasting of the hand
  • other neurological features establish the diagnosis

Cuff lesions

  • with supraspinatus tendon lesions pain sometimes radiates to the arm and hand
  • shoulder movement is abnormal and painful

Treatment

Conservative

  • most patients managed
  • exercises to strengthen the shrugging muscles, postural training and instruction in ways of preventing shoulder droop or muscle fatigue
  • analgesics when necessary

Operative treatment

indicated

    • pain severe
    • muscle wasting is obvious
    • vascular disturbances
  • thoracic outlet is decompressed by removing the first rib (or the cervical rib)
  • best accomplished by the transaxillary approach, but care must be taken to prevent injury to the brachial plexus and subclavian vessels, or perforation of the pleura (Roos, 1966)