Thoracic outlet syndrome (TOS) may affect neurologic or vascular structures, or both, depending on the component of the neurovascular bundle predominantly compressed.
Types include neurologic, arterial, venous, and neurovascular/combined, and patients may present with signs and symptoms of nerve, vein, or artery compression or any combination of these. Neurologic is the most common, while arterial, which is relatively rare, is arguably the most important to recognize owing to the risk of ischemia.
Neurologic TOS primarily develops spontaneously in people in their late teens up to the age of 60 years, and is more common in women. It usually occurs in the setting of congenital abnormalities of the thoracic outlet, hyperextension injuries, repetitive stress injuries (e.g., work related), and external compressing factors (e.g., poor posture).
Patients with venous or arterial occlusion require prompt evaluation for surgical intervention with thrombolysis and thoracic outlet decompression.
For most cases of disputed neurologic thoracic outlet syndrome, initial management is conservative and includes physical therapy. Surgical management of nerve compression is indicated in individuals who show physical signs of nerve damage or who have failed conservative treatments.
Thoracic outlet syndrome (TOS) refers to the compression of one or more of the neurovascular structures traversing the superior aperture of the chest. The thoracic outlet is the area between the neck and shoulder, over the top of the thorax, and under the clavicle to the axilla.
Knowledge of the thoracic outlet anatomy is fundamental to the diagnosis of any type of TOS. The subclavian artery leaves the thorax by arching over the first rib behind the scalenus anticus muscle (anterior scalene) and in front of the scalenus medius muscle (middle scalene). It then passes under the clavicle and finally enters the axilla beneath the pectoralis minor muscle. The subclavian vein has an identical course, except that it passes anteriorly rather than posteriorly to the scalenus anticus muscle. The brachial plexus follows the route of the subclavian artery, but it lies a little more posteriorly and laterally. The axillary-subclavian vein traverses the tunnel formed by the clavicle and subclavius muscle anteriorly, the scalenus anticus muscle laterally, the first rib posterior-inferiorly, and the costoclavicular ligament medially. The anatomical areas within the thoracic outlet that can typically impart neurovascular compromise include the interscalene triangle, the costoclavicular space, and the subcoracoid space, although it is possible that the sternal-costovertebral bony circle may also be involved.
History and exam
Key diagnostic factors
- history of repetitive jobs or overhead hobbies/activities
- pain in upper extremity and adjacent areas
- paresthesias in arms, hands, and/or fingers
- circulatory changes in upper extremity
- upper extremity fatigue
Other diagnostic factors
- history of clavicular fracture
- history of cardiovascular or thoracic surgery
- palpation of cervical rib
- subcutaneous venous collateral around shoulders (Urschel sign)
- motor weakness
- thenar eminence muscle atrophy
- exertional pain/claudication
- supraclavicular systolic bruit
- blood pressure difference between extremities
- positive Adson (scalene) test
- positive costoclavicular test
- positive hyperabduction test
- positive Roos test
- positive stretch test
- positive upper limb tension tests
- positive Wright maneuver
- edema/swelling of upper extremity
- cervical rib or bony abnormalities
- poor posture
- repetitive overhead activity
- motor vehicle collisions
- large breasts or implants
- age (late teens to 60 years)
- female sex
- history of poliomyelitis
- median sternotomy
1st investigations to order
- cervical spine x-ray
- Electromyography/nerve conduction velocity
- CT angiography
- Doppler ultrasonography
Investigations to consider
- MRI neck/clavicle/shoulder
- muscle block
- conventional arteriography
- magnetic resonance angiography (MRA)
- contrast venography
- magnetic resonance venography (MRV)
- CBC and coagulation studies
neurologic TOS (NTOS)
arterial TOS (ATOS)
venous TOS (vTOS)
Chaney Stewman, MD
Sports Medicine Fellow
Christiana Care Health Services
Department of Family and Community Medicine
CS is the author of a reference cited in this topic.
Marc I. Harwood, MD
Department of Family and Community Medicine
Jefferson Medical College
Thomas Jefferson University
MIH is the author of a reference cited in this topic.
Dr Chaney Stewman and Dr Marc I. Harwood would like to gratefully acknowledge Dr Pedro K. Beredjiklian, Dr Peter C. Vitanzo, Dr Harold C. Urschel Jr, Rachel Montano, and Brenda Knee, previous contributors to this topic. PKB has stock ownership in Wright Medical Inc. PCV is the author of a reference cited in this topic. HCU is an author of several references cited in this topic. RM and BK declare that they have no competing interests.
Ian Loftus, BSc, MB, ChB, FRCS, MD
Professor of Vascular Surgery
St. George's NHS Healthcare Trust
IL declares that he has no competing interests.
Scott R. Laker, MD
University of Colorado School of Medicine
SRL is the author of a reference cited in this topic.
John A. Kern, MD
University of Virginia School of Medicine
JAK declares that he has no competing interests.
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