April 30, 2014
May 6, 2014



Cluster of Neurogenic or vascular symptoms caused by the compression of the neurovascular bundle at the thoracic outlet (1)


Cervical rib syndrome, Scalene Anticus syndrome, Costoclavicular syndrome, Hyperabduction syndrome



Boundaries of Thoracic Outlet – Spinal Column, First Rib, Sternum

Neurovascular Compression in 3 possible spaces

  1. Scalene Triangle – Most common site of brachial plexus compression. Bounded by Anterior/Middle Scalene and first rib. Cervical and anomalous rib compression point
  2. Costo-clavicular space – Area between first rib and clavicle. Subclavian vein compression at this site
  3. Pectoralis minor space – Area between Pec minor and chest wall. 2nd most common site of neurovascular compression

Etiology and Pathogenesis:

Combination of genetic predisposition and trauma – acute or chronic/repetitive

Anatomic predisposition separated into Soft tissue (70%) and Osseous Abnormalities (30%) (2)

Soft Tissue Abnormalities

  • Scalene muscle insertion variation
  • Scalene muscle hypertrophy
  • Scalenous Minimus accessory muscle, found in 30-50% of TOS patients.
  • Costocoracoid ligament – implicated in Paget-Schroetter Syndrome, venous TOS with thrombosis
  • Soft tissue tumors

Osseous Abnormalities

  • Cervical ribs,
  • Prominent C7 Transverse Process,
  • Callous from 1st rib fracture
  • Clavicle malunion
  • AC joint injury
  • Osseous tumor


None available – likely secondary to differing definitions sited

Classic patient, young thin female, forward posture with neck flexion and anteriorly located glenohumeral joint (1)

 Clinical Features:

90% Neurogenic, 3% Venous, <1% Arterial

Neurogenic TOS

  • Upper extremity weakness and paresthesia.
  • Non-radicular pattern distinguishes from Carpal Tunnel and Cervical radiculopathy.
  • Headaches and neck pain also possible
  • Triggered by sustained overhead/repetitive movement

Vascular TOS

  • Deep pain in upper extremities and chest, worse with movement. May have cyanotic appearance from Subclavian vein compression.
  • Dilated collateral superficial veins
  • Paget-Schroetter syndrome is subclavian vein thrombosis after repetitive injury in young/healthy individuals.

Aterial TOS

  • Very rare, subclavian artery compression from a cervical rib.
  • Arm Claudication
  • Risk of aneurysm formation, thrombosis, limb ischemia.

 Differential Diagnoses:

  • C-spine pathology
  • Intrinsic Shoulder Pathologies
  • Peripheral neuropathies


  • Gallant-Sumner Hand: Atrophy of Abductor Policus Brevis, hypothenar musculature, interossei
  • Vascular Findings: Blood pressure differences >20 between arms, upper extremity, chest wall congestion
  • Supraclavicular masses/tenderness
  • Wright Test, Allen test  Wright Test or Allen Test TOS

Figure 2 – Allen test/Wright Test :Arm abducted and in posterior scaption, with head turned in contralateral direction to tested side.  +ve test is loss of pulse.

  • Roos Test (Specificity 30%)Roos Test TOS

Figure 3 – Roos Test:  Patient is asked to hold flexed pose, inability to hold pose on affected side represents a positive test.

  • Adson Test (Specificity 76%) – (3

)Adson Test TOS

Figure 4 – Adson test:  Patient’s arm is held in extension and 30 deg of abduction with head turned towards/ispilaterally to affected arm.  Loss of pulse results in a positive test.

  • Pulse Oximetry differences – (4)


  • CXR – Cervical ribs, C7 Transverse processes, shoulder girdle abnormalities (5)
  • CT/MRI – Space occupying lesions, post-traumatic deformity, soft-tissue anomalies
  • U/S for Venous TOS – (92% Specificity, 95% Sensitivity) (6)
  • EMG/Nerve Conduction studies (median antebrachial cutaneous nerve)
  • Anterior scalene blocks (diagnositic and prognostic)

Management: (Evidence Based)

Non-Operative (7)

  • Education (Relaxation techniques, postural mechanics, weight/nutrition control), Activity Modification (Limiting repetitive overhead movements, employment modification), Physical Therapy (Stretching, ROM, Nerve gliding techniques)
  • Trial of NSAIDs, Muscle Relaxants

Operative (8)

  • Typically reserved for patients who fail 6 months of conservative treatment [Kuhn]
  • Vascular TOS patients without contraindications
  • Transaxillary, Supravicular, Posterio approaches described
  • Complications: Pneumothorax, Subclavian Artery/Vein injury, Thoracic duct injury, Brachial Plexus injury, failure to decompress thoracic outlet

Dr. Daniel Abourbih (October 20, 2015 PR ND)


1) Kuhn JE, Lebus V GF, Bible JE. Thoracic outlet syndrome. J Am Acad Orthop Surg. 2015 Apr;23(4):222-32

2) Makhoul RG, Machleder HI. Developmental anomalies at the thoracic outlet: an analysis of 200 consecutive cases. J Vasc Surg. 1992 Oct;16(4):534-42

3) Gillard J, Pérez-Cousin M, Hachulla E, Remy J, Hurtevent JF, Vinckier L, Thévenon A, Duquesnoy B. Diagnosing thoracic outlet syndrome: contribution of provocative tests, ultrasonography, electrophysiology, and helical computed tomography in 48 patients. Joint Bone Spine. 2001 Oct;68(5):416-24.

4) Braun RM, Rechnic M, Shah KN. Pulse oximetry measurements in the evaluation of patients with possible thoracic outlet syndrome. J Hand Surg Am. 2012 Dec;37(12):2564-9

5) Cho YJ, Lee HJ, Gong HS, Rhee SH, Park SJ, Baek GH. The radiologic relationship of the shoulder girdle to the thorax as an aid in diagnosing neurogenic thoracic outlet syndrome. J Hand Surg Am. 2012 Jun;37(6):1187-93

6) Longley DG, Yedlicka JW, Molina EJ, Schwabacher S, Hunter DW, Letourneau JG. Thoracic outlet syndrome: evaluation of the subclavian vessels by color duplex sonography. AJR Am J Roentgenol. 1992 Mar;158(3):623-30

7) Novak CB, Collins ED, Mackinnon SE. Outcome following conservative management of thoracic outlet syndrome. J Hand Surg Am. 1995 Jul;20(4):542-8

8) Urschel HC Jr, Razzuk MA. Neurovascular compression in the thoracic outlet: changing management over 50 years. Ann Surg. 1998 Oct;228(4):609-17.