Neurogenic TOS

1. Thoracic Outlet
Syndrome (TOS)
ADE WIJAYA, MD
September 2017
“Thoracic outlet syndrome (TOS) is an uncommon condition that can
happen when the nerves, artery, or vein to the arm is compressed
by one or more structures that make up the thoracic outlet.”
Grunebach, H., Arnold, M. W., & Lum, Y. W. (2015). Thoracic outlet syndrome.Vascular Medicine, 20(5), 493-495.
Focus on electrodiagnostic study

2. Clinical Summary
Grunebach, H., Arnold, M. W., & Lum, Y. W. (2015). Thoracic outlet syndrome.Vascular Medicine, 20(5), 493-495.

3. Neurogenic TOS Anatomy

4. Electromyography and Neuromuscular Disorders 3rd Edition. Preston

5. Neurogenic TOS
68 %  lower plexus compression
20 %  both upper and lower plexus compression
12 %  upper plexus compression
Magill, S. T., Brus-Ramer, M., Weinstein, P. R., Chin, C. T., & Jacques, L. (2015). Neurogenic thoracic outlet syndrome: current diagnostic criteria and advances in MRI diagnostics. Neurosurgical focus, 39(3), E7.

6. Electromyography and Neuromuscular Disorders 3rd Edition. Preston

7. Electromyography and Neuromuscular Disorders 3rd Edition. Preston

8. Brachial Plexus Anatomy

9. Nerve Conduction Studies in TOS
Spared Median SNAP which is innervated by
superior and medial trunks

11. Summary
1. TOS : Neurogenic vs Vascular
2. Neurogenic TOS  Lower trunk lesion
3. EMG & NCS procedure for lower trunk lesion
- Spared Median SNAP
- Bilateral examination
- Median cutaneous antebrachial nerve is the most common nerve affected
- Median motor nerve (thenar muscle) are more affected than ulnar one
- Collision study