Thoracic Outlet Syndrome: What is it?
Written by: Lisette Brown PA-C, BMedSc, LMT, RMT
June 9th, 2022
Diagnosing and Tests for TOS
About my history with Thoracic Outlet Syndrome
After I graduated from college, texting became the way of communicating on phones, internet surfing increased, patient charting was now online, so time on the computer increased, and poor posture in general. I started to notice that my forearms started to feel heavy and I felt they were inflamed. I would shake them out and stretch my forearms when I remembered and when I had time after charting on patients and/or after a massage therapy session. My symptoms started to progress: usually after a long day in the ER, when I found myself texting a lot or internet surfing on my phone, and I even started to wake up with symptoms. My symptoms included (to both upper extremities):
1. Heaviness
2. Numbness and Tingling in the arms and fingers
3. Tightness and Soreness to neck and chest
4. Pain in the neck, shoulder, or hand
5. Weakness in my grip strength
I had cohorts do neurological testing and also TOS testing on me, without significant findings. It was first suggested that I had carpal tunnel syndrome, cubital tunnel syndrome, and/or cervical radiculopathy. Diagnostic tests did not show any abnormalities. “True” Neurogenic Thoracic Outlet Syndrome and/or “Disputed” Neurogenic Thoracic Outlet Syndrome were never on the table for diagnosis. Thus, I was diagnosed with muscle tension, anxiety and peripheral neuropathy. Strange, since I had not had any problems prior and now, I am being diagnosed with peripheral neuropathy already? My healthcare providers wanted to place me on medications for neuropathy. I was 28 at the peak of my symptomology. It started intermittently since I was 26 years old and I kept dismissing my concerns with excuses, “I slept wrong,” “I must have tweaked my neck,” “It’ll go away on its own.” I did not want to be on medications already, for an unknown cause of symptoms. I tried doing stretches on my forearms, scalene muscles, pectoralis major and minor muscles, which would resolve my symptoms for a few minutes.
I began massage school at the end of 2008. We did not start clinical type massage until 2009. Everyday I was receiving a massage and giving a massage at school. My classmates and I were able to treat each other everyday. When we would have time, I would specifically have my partner work on my scalenus, pecs, and forearms, which reproduced my symptomology, so I knew these areas were a part of the cause of my symptoms. By the third massage specifically to these areas that were provided by my instructors and classmates my symptoms resolved.
I do on occasion have a return of my symptoms; however, I know what I need to do: checking with my posture and correct it, decrease screen time on phone and computer (decreasing amount of time my elbows are flexed, decreasing the amount of time I’m in a forward head posture and decreasing the amount of time my shoulders are slouched), stretch, and get weekly or every other week massages. Even as I type right now, I feel paresthesias (numbness and tingling) to my fingers and elbow area, along with neck and pectoralis pain. However, I have been on the computer and on my phone for the past 3 days figuring out how to write a blog and then writing my first one. So, I know after I am done with this article, I’ll need to take a break.
Anatomy of the Thoracic Outlet/Inlet (TOS):
From the articles and studies I have read recently, there is debate on how to diagnose TOS, what tests to do to diagnose TOS, the number of types of TOS, if this syndrome truly exists, and if the name of the syndrome is correct. “…the actual site of pathology is technically the thoracic "inlet," not the "outlet." The primary controversy seems to center around the lack of objective criteria for diagnosis and the confusion with multiple types or clinical presentations.”(1) Symptoms often are confused with various distal compression neuropathies or cervical radiculopathies.
The thoracic outlet is the ring formed by the top ribs, just below the collarbone. There are 3 important spaces in the thoracic outlet, which are already small in size and reduce further with arm movement:
The first space is the InterScalene Triangle-the borders are the anterior scalene muscle, middle scalene muscle, and the first rib. This space contains an important nerve bundle called the brachial plexus and the subclavian artery. Unfortunately, this is one of the principal sites for compression of the nerves and/or subclavian artery causing TOS. As the neurovascular bundle move distally, they arrive to the second space. (2,3)
The second space is the Costoclavicular Space-it is bound by the subclavius muscle, the clavicle, the first rib, the anterior scalene, the costoclavicular ligament, and the upper scapula border. Now both the subclavian artery and subclavian vein with the brachial plexus travel together. Progressing further distally prior to the axilla (arm pit) the neurovascular bundle arrives at the third space. (2,3)
The final space is the Subpectoralis Minor Space or Subcoracoid Space- it is bordered by the pectoralis minor muscle, the coracoid process, and the ribs 2-4. The subclavian vein, subclavian artery and the brachial plexus travel underneath the pectoralis minor tendon. Along with the Scalene Triangle, these 2 compartments account for the most common sites for nerve and/or vessel compression in TOS. (2,3)
Compartment | Borders | Contents |
Interscalene Triangle | Anterior: Anterior Scalene Mus. Posterior: Middle Scalene Mus. Inferior: First Rib | Brachial Plexus Trunks Subclavian Artery |
Costoclavicular Space | Anterior: Clavicle and Subclavius Mus. Posterior: First Rib and Anterior Scalene Mus. Medial: Costoclavicular Ligament Lateral: Upper Scapular Border | Brachial Plexus Divisions Subclavian Artery Subclavian Vein |
Subpectoralis Minor Space/Subcoracoid Space | Anterior: Pectoralis Minor Mus. Posterior: Ribs 2-4 Superior: Coracoid | Brachial Plexus Cords Axillary Artery Axillary Vein |
Stephen Kishner, MD, MHA. (2015, August 12). Brachial Plexus Anatomy. https://emedicine.medscape.com/article/1877731-overview
Laura Gruber, MD, Deepthi Ganta, MD, et al. (2012, December 28). Thoracic Outlet Syndrome. https://now.aapmr.org/thoracic-outlet-syndrome/
Margaret R. Connolly, MD and Hugh G. Auchincloss, MD, MPH. (2021, February; 31(1): 1-10). Thoracic Surgery Clinic. Anatomy and Embryology of the Thoracic Outlet. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8057296/
What is Thoracic Outlet Syndrome (TOS)?
“Thoracic outlet syndrome (TOS) involves compression, injury, or irritation to the neurovascular structures at the root of the neck or upper thoracic region…” (1) Thoracic outlet syndrome (TOS) is a broad term to describe a disorder/ailment that develops when the neurovascular bundle that occupies the thoracic outlet/inlet are compressed in any one of the compartments discussed above. Research states that this syndrome is primarily neurological, accounting for approximately 95% of cases, most commonly found in women more than men, and in the 20-40 age group. (5,6) Therefore, it mainly involves the neural bundle named the brachial plexus, “most often the lower trunk or medial cord; alternatively, it could involve compression of the subclavian artery and/or vein. Thrombosis, embolus, or aneurysm of these vessels is a less likely possibility.” (1)
TOS is categorized into 5 adaptations based on pathophysiology: Arterial, Venous, Traumatic Neurovascular, True Neurogenic, and Disputed. There are experts that argue Disputed TOS does not exist and is better correlated with a cervicoscapular issue, however, for this blog purpose I am including this as part of TOS. Of the 5 categories, the disputed is the most difficult to diagnose because it does not follow any of the diagnostic features that is expected of TOS consistently, it masks itself in other diagnoses that exhibit similar symptoms. Thus, the delay in diagnosis and care. As a massage therapist I feel that the disputed and/or neurological TOS are actually more frequent in the cause of symptoms than studies have shown when calculating percentages of overall etiologies of upper limb pain, paresthesia, and weakness. (7,8)
There was one article I read that discussed a new term, for a 6th category or maybe to replace the Disputed TOS term, Postural Thoracic Outlet Syndrome. (1) I feel that this is a great new term and category for a majority of the clients that I treat have postural issues due to desk work, computer work, prolonged phone time, texting, driving, etc. Universally, the greater part of our days is in a forward head posture, shoulders protracted and internally rotated position. We live in a flexed positional world. How could we not have symptoms due to posture?
Causes of TOS
Since the 3 main compartments, discussed previously, are already small any type of prolonged and repetitive pressure on neurovascular bundle coursing through the compartments creates symptoms. Pressure may be caused by an extra rib in the neck, slouched shoulders, overzealous weight lifting program, from sports, and muscle weakness. In addition, causes may include arm and/or shoulder overextension, laying in an unusual position, or having a firm object under the neck or arm for a prolonged period.
Congenital (Since Birth) | Acquired (Through course of life) |
Cervical Rib/Supernumerary Rib (a rib arising from the cervical spine, most commonly level 7) | Poor Posture (Forward head posture, rounded shoulders) |
Exostosis (extra growth of bone, i.e., bone spur)/Tumor of First Rib or Clavicle | Falls/Injuries/Traumas to Upper limb |
Elongated transverse process of C7 vertebra | First Rib and/or Clavicle Fracture with significant callus |
Fibromuscular bands going from C7 to the First Rib | Hypertrophy (increase in muscle size) of anterior scalene and/or pectoralis minor muscle-weightlifting, playing sports baseball, swimming, gymnastics |
Deviations of where the Scalene muscles insert | Whiplash Injury |
Accessory (Extra) Scalene Muscle | Repetitive stress injuries/repetitive movements from activities or occupation (arm elevation and pressure on joints-hair dressers, barbers, assembly line workers, movers, industrial workers, cashiers, carrying a heavy bag/purse on shoulder, obesity; head and/or shoulders flexed forward-receptionist, gamers, desk/computer workers, musicians, holding a baby for a prolonged period) |
Scoliosis (abnormal curvature) of cervical spine | Surgical adhesions (scar tissue) |
Karl A. Illig, MD, Dean Donahue, MD, et al. (2016, September). Journal of Vascular Surgery, Vol. 64, Issue 3, Pe23-e35. Reporting standards of the Society for Vascular Surgery for thoracic outlet syndrome. https://www.sciencedirect.com/science/article/pii/S0741521416301914
Margaret Clarke Tracci, MD, JD. (2011, December 01). General Thoracic Surgery, Vol. 16, Issue 4, P267-277. Thoracic Outlet Syndrome: Transaxillary Approach. https://www.optechtcs.com/article/S1522-2942%2812%2900002-5/fulltext
Benjamin M Sucher, DO, FAOCPMR, FAAPMR. (2021, October 21). Physical Medicine and Rehabilitation for Thoracic Outlet Syndrome. https://emedicine.medscape.com/article/316715-overview
Csakai, C DC, Carlin, D DC, Centofanti, J DC. Thoracic outlet syndrome: a crushing nerve or vascular injury. https://esportshealthcare.com/thoracic-outlet-syndrome/
Symptoms of TOS
“The symptoms of true and disputed TOS are largely the same, though objective findings from motor nerve conduction studies and needle electromyography are notably absent in the disputed variety.” (12) Symptoms vary from all the 5 TOS varieties and depend on the structures that are compressed.
1. Neck pain may radiate to ear and base of skull
2. Specific muscles trapezius, rhomboid, pectoralis, deltoid, forearm pain
3. Shoulder and/or arm, chest pain
4. Supraclavicular pain
5. Occipital headache
6. Numbness/tingling to arm and/or fingers
7. Muscle atrophy (decrease in size, muscle wasting) rare
1. Arm and hand swelling
2. Bluish or reddish discoloration of extremity
3. Fatigue, tightness, heaviness
4. Distension of veins, blood clots
5. Cold/pale fingers
6. Weak or no pulse in affected extremity
7. Chronic arm fatigue or pain with movement (claudication)
8. Non healing wounds/ulcers
9. Sudden hand pain/weakness
10. Numbness/tingling in fingers
Diagnosing and Tests for TOS
Most important is gathering the history of the symptoms: onset, location, characteristics of the discomfort, symptoms, aggravating and alleviating factors, etc. Followed by an assessment or physical exam. Then performing provocative tests (tests that elicit symptoms of TOS with positions that would compress the nerves in one of the 3 compartments). Lastly, if needed diagnostic tests (radiography, doppler sonography, computed tomography (CT), magnetic resonance imaging (MRI), EMG, venous angiography). (1,6,12)
Provocative tests:
https://viasonix.com/vascular-angiology/thoracic-outlet-syndrome/
Leonhard, V, Caldwell, G, et al. (2017, July 4). Ultrasonographic Diagnosis of Thoracic Outlet Syndrome Secondary to Brachial Plexus Piercing Variation. https://www.semanticscholar.org/paper/Ultrasonographic-Diagnosis-of-Thoracic-Outlet-to-Leonhard-Caldwell/7eb3587b2e6f801ec0b01c1e333079f5b8c59330
Gillard J, Pérez-Cousin M, Hachulla E, et al. (2001, October). Joint Bone Spine 68(5):416-424. Diagnosing thoracic outlet syndrome: contribution of provocative tests, ultrasonography, electrophysiology, and helical computed tomography in 48 patients. https://pubmed.ncbi.nlm.nih.gov/11707008/
Treatment of TOS
There are conservative treatments and surgical treatments for TOS. The treatment relies on the cause of TOS, the patient, and healthcare provider. It is common practice to start with conservative methods, except in patients who symptoms are emergent, such as seen in arterial TOS; severe compression resulting in debilitating symptoms.
The most invasive treatment is the path of surgery. There are numerous surgical procedures to treat the cause of TOS; it is contingent on the location of compression as to which procedure will be completed. Surgery is reserved for the most severe of cases and most emergent of cases, where conservative therapy would cause a delay in treatment resulting in poor outcome; it is also reserved for those patients who have had several months of conservative treatment with continued progression of symptoms. (1,6,12,16)
Conservative treatment includes lifestyle modifications, physical therapy, rehabilitation, pharmacological, and I add, massage therapy:(16)
1. Pharmacological
· Anti-inflammatories
· Muscle Relaxants
· Opioid pain medication
· Trigger point injections (anesthetic alone or with a steroid)
2. Therapeutic Modalities
· Heat/Cold compresses
· Transcutaneous Electrical Nerve Stimulation
· Education
Posture
Ergonomics (avoidance or activity modification that exacerbation symptoms)
Exercise with proper body posture
Relaxation (deep breathing, contract-relax exercises)
· Physical Therapy
Exercises:
Stretching upper trapezius, scalene, and pectoral muscles
Strengthening the cervical extensors, scapular adductors, shoulder retractors
Chin tucks
Neck stretches
Shoulder stretches
· Massage Therapy
Deep tissue, Trigger Point, Myofascial Release (Connective Tissue) Massage to the muscle belly and attachment site; Muscle Energy Techniques; Pin and Stretches; Passive Stretching; Active Release Techniques, and Joint Mobility to the:
Scalene muscles
Pectoral muscles, especially Pectoralis Minor
Sternocleidomastoid muscles
Trapezius, especially upper portion
Levator Scapula
Suboccipital muscles
Sternoclavicular Joint
Scapula
First rib articulations
Acromioclavicular mobilization
· Chiropractic Therapy
· Control of swelling (edema)
Compression garments
Lymphatic drainage massage
Active range of motion
Exercises for TOS
Petrie, T DPT, OCS, Medical reviewed by Campedelli, L, PT, DPT. (2021, July 30). What to Expect in Thoracic Outlet Syndrome Physical Therapy? https://www.verywellhealth.com/thoracic-outlet-syndrome-physical-therapy-5192098
Active Chiropractic. (2015, August 18). Thoracic Outlet Syndrome Exercises. https://activechiro.ca/thoracic-outlet-syndrome-exercises/
References
1. Benjamin M Sucher, DO, FAOCPMR, FAAPMR. (2021, October 21). Physical Medicine and Rehabilitation for Thoracic Outlet Syndrome. https://emedicine.medscape.com/article/316715-overview
2. Margaret R. Connolly, MD and Hugh G. Auchincloss, MD, MPH. (2021, February; 31(1): 1-10). Thoracic Surgery Clinic. Anatomy and Embryology of the Thoracic Outlet. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8057296/
3. Daryl A. Rosenbaum, MD. (2019, January 10). What anatomy of the thoracic outlet relevant to thoracic outlet syndrome? https://www.medscape.com/answers/96412-181544/what-anatomy-of-the-thoracic-outlet-relevant-to-thoracic-outlet-syndrome
4. Stephen Kishner, MD, MHA. (2015, August 12). Brachial Plexus Anatomy. https://emedicine.medscape.com/article/1877731-overview
5. Laura Gruber, MD, Deepthi Ganta, MD, et al. (2012, December 28). Thoracic Outlet Syndrome. https://now.aapmr.org/thoracic-outlet-syndrome/
6. Petrie, T DPT, OCS, Medical reviewed by Campedelli, L, PT, DPT. (2021, July 30). What to Expect in Thoracic Outlet Syndrome Physical Therapy? https://www.verywellhealth.com/thoracic-outlet-syndrome-physical-therapy-5192098
7. Mark A. Ferrante, MD and Nicole D. Ferrante. (2017, June; 55(6): 782-293). The Thoracic Outlet Syndromes: Part 1. Overview of the Thoracic Outlet Syndromes and Review of True Neurogenic Thoracic Outlet Syndrome. https://hmlfunctionalcare.com/wp-content/uploads/2021/06/TOS-Part-1.pdf
8. Jacky Laulan, Bernard Fouquet, et al. (2011, September; 21(3): 366-373). J Occupational Rehabilitation. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3526474/
9. Karl A. Illig, MD, Dean Donahue, MD, et al. (2016, September). Journal of Vascular Surgery, Vol. 64, Issue 3, Pe23-e35. Reporting standards of the Society for Vascular Surgery for thoracic outlet syndrome. https://www.sciencedirect.com/science/article/pii/S0741521416301914
10. Margaret Clarke Tracci, MD, JD. (2011, December 01). General Thoracic Surgery, Vol. 16, Issue 4, P267-277. Thoracic Outlet Syndrome: Transaxillary Approach. https://www.optechtcs.com/article/S1522-2942%2812%2900002-5/fulltext
11. Csakai, C DC, Carlin, D DC, Centofanti, J DC. Thoracic outlet syndrome: a crushing nerve or vascular injury. https://esportshealthcare.com/thoracic-outlet-syndrome/
12. Mark R. Jones, Amit Prabhakar, et al. (2019, June 8; online 2019 April 29). Pain Ther. Thoracic Outlet Syndrome: A Comprehensive Review of Pathophysiology, Diagnosis, and Treatment. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6514035/
14. Leonhard, V, Caldwell, G, et al. (2017, July 4). Ultrasonographic Diagnosis of Thoracic Outlet Syndrome Secondary to Brachial Plexus Piercing Variation. https://www.semanticscholar.org/paper/Ultrasonographic-Diagnosis-of-Thoracic-Outlet-to-Leonhard-Caldwell/7eb3587b2e6f801ec0b01c1e333079f5b8c59330
15. Gillard J, Pérez-Cousin M, Hachulla E, et al. (2001, October). Joint Bone Spine 68(5):416-424. Diagnosing thoracic outlet syndrome: contribution of provocative tests, ultrasonography, electrophysiology, and helical computed tomography in 48 patients. https://pubmed.ncbi.nlm.nih.gov/11707008/
16 Shin, N. (2012). Thoracic Outlet Syndrome. http://morphopedics.wikidot.com/thoracic-outlet-syndrome
18. Active Chiropractic. (2015, August 18). Thoracic Outlet Syndrome Exercises. https://activechiro.ca/thoracic-outlet-syndrome-exercises/
