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)