Thoracic Outlet Syndrome is commonly explained as compression within the interscalene triangle, but this description captures only part of the anatomical reality. In clinical observation, focusing on a single space often fails to explain persistent or recurring symptoms.
The thoracic outlet is composed of three thoracic outlet passageways that function together as a mechanical system. These include the scalene triangle, the costoclavicular space, and the subcoracoid region beneath the pectoralis minor.
Understanding all three spaces is essential for recognizing why many individuals continue to experience symptoms even after invasive procedures such as first rib resection or pectoralis minor tenotomy.
The scalene triangle lies between the anterior and middle scalene muscles as they attach to the first rib. The brachial plexus and subclavian artery pass through this narrow region.
When scalene muscles become tight, inflamed, or chronically contracted, the space narrows. This can contribute to nerve and vessel irritation, leading many individuals to focus solely on this region as the source of symptoms.
However, compression rarely occurs in isolation. The second region, the costoclavicular space, sits between the clavicle and the first rib and is highly sensitive to posture and shoulder position.
Chronic shoulder depression, forward head posture, and sustained contraction of chest and neck muscles can significantly narrow this space. Many individuals describe heaviness, tingling, or vascular symptoms when the clavicle presses downward toward the rib cage.
The third and most frequently overlooked region is the subcoracoid compression zone beneath the coracoid process. This space is strongly influenced by muscles involved in forward arm use.
Muscles attaching here include the pectoralis minor, coracobrachialis, and biceps short head. These muscles activate during phone use, computer work, grooming, clinical care, and prolonged reaching tasks.
With repeated activation, these muscles develop chronic muscle contraction and fatigue. Fatigued muscle tissue accumulates inflammation, increasing tension across the shoulder and chest.
As these muscles tighten, they pull the shoulder downward while simultaneously contributing to rib cage elevation. This creates a dual-direction compression pattern that narrows all three thoracic outlet spaces at once.
In my clinical experience, the pectoralis minor can elevate the entire rib cage into the outlet rather than affecting only the first rib. This contradicts the common assumption that first rib position alone explains compression.
Many surgical approaches focus primarily on first rib resection outcomes or scalene removal. While these procedures alter anatomy, they do not automatically restore balance within the larger mechanical system.
Even after surgery, muscles such as the coracobrachialis, biceps short head, and subclavius may continue to depress the shoulder. This can maintain compression of the subclavian vein and artery despite structural removal.
Individuals often report swelling, color changes, coldness, weakness, or altered grip strength due to this persistent mechanical force. These symptoms reflect ongoing compression rather than surgical failure.
As the rib cage elevates into the outlet, the T1 nerve root involvement may occur at the base of the neck. This frequently presents as tingling in the ring and pinky fingers.
These sensory changes are commonly labeled as neurogenic TOS symptoms, yet they arise from global mechanical distortion rather than a single entrapped structure.
This reflects a larger upper body spring system that becomes twisted through guarding, internal compression, and chronic muscle tension. The system behaves as an integrated unit, not isolated parts.
To illustrate this interaction, I commissioned a detailed anatomical illustration demonstrating how rib elevation and shoulder depression occur simultaneously during severe compression.
This illustration has been published by vascular surgeons in both Italy and the United States. They recognize the model because it visually confirms what occurs within the thoracic outlet during advanced compression.
The rib cage elevates like a platform, while the shoulder depresses like a lever. Together, these forces collapse the tunnel through which nerves and vessels must pass.
Surgery removes tissue, but it does not unwind decades of muscle guarding and splinting patterns. Without addressing the system as a whole, compression forces may persist.
Understanding all three thoracic outlet spaces clarifies why chronic pain, numbness, swelling, and weakness can remain after aggressive intervention.
Education helps individuals recognize that persistent symptoms are not random. They reflect a mechanical system that has adapted to long-term load and tension.
Recognizing this three-space model provides clarity and explains why restoring balance within the spring system is essential for long-term symptom resolution.
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References
- Roos, D. B. “Thoracic Outlet Syndrome Is Underdiagnosed.” Muscle & Nerve 22, no. 1 (1999): 126–129.
- Sanders, Richard J., and Neal S. Pearce. “Neurogenic Thoracic Outlet Syndrome.” Journal of Vascular Surgery 36, no. 3 (2002): 669–676.
- Urschel, Harold C., and R. B. Razzuk. “The Neurovascular Compression Syndromes of the Thoracic Outlet.” Annals of Thoracic Surgery 50, no. 3 (1990): 484–490.
Dr James Stoxen DC., FSSEMM (hon) He is the president of Team Doctors®, Treatment and Training Center Chicago, one of the most recognized treatment centers in the world.
Dr Stoxen is a #1 International Bestselling Author of the book, The Human Spring Approach to Thoracic Outlet Syndrome. He has lectured at more than 20 medical conferences on his Human Spring Approach to Thoracic Outlet Syndrome and asked to publish his research on this approach to treating thoracic outlet syndrome in over 30 peer review medical journals.
He has been asked to submit his other research on the human spring approach to treatment, training and prevention in over 150 peer review medical journals. He serves as the Editor-in-Chief, Journal of Orthopedic Science and Research, Executive Editor or the Journal of Trauma and Acute Care, Chief Editor, Advances in Orthopedics and Sports Medicine Journal and editorial board for over 35 peer review medical journals.
He is a much sought-after speaker. He has given over 1000 live presentations and lectured at over 70 medical conferences to over 50,000 doctors in more than 20 countries. He has been invited to speak at over 300 medical conferences which includes invitations as the keynote speaker at over 50 medical conferences.
After his groundbreaking lecture on the Integrated Spring-Mass Model at the World Congress of Sports and Exercise Medicine he was presented with an Honorary Fellowship Award by a member of the royal family, the Sultan of Pahang, for his distinguished research and contributions to the advancement of Sports and Exercise Medicine on an International level. He was inducted into the National Fitness Hall of Fame in 2008 and the Personal Trainers Hall of Fame in 2012.
Dr Stoxen has a big reputation in the entertainment industry working as a doctor for over 150 tours of elite entertainers, caring for over 1000 top celebrity entertainers and their handlers. Anthony Field or the popular children’s entertainment group, The Wiggles, wrote a book, How I Got My Wiggle Back detailing his struggles with chronic pain and clinical depression he struggled with for years. Dr Stoxen is proud to be able to assist him.
Full Bio) Dr Stoxen can be reached directly at teamdoctors@aol.com
