24/05/2026
Differencial diagnosis see T4 syndrome!
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𝗗𝗶𝗮𝗴𝗻𝗼𝘀𝘁𝗶𝗰 𝗰𝗿𝗶𝘁𝗲𝗿𝗶𝗮 𝗳𝗼𝗿 𝗻𝗲𝘂𝗿𝗼𝗴𝗲𝗻𝗶𝗰 𝘁𝗵𝗼𝗿𝗮𝗰𝗶𝗰 𝗼𝘂𝘁𝗹𝗲𝘁 𝘀𝘆𝗻𝗱𝗿𝗼𝗺𝗲 (𝗻𝗧𝗢𝗦)- 𝗔𝗻 𝗘𝘅𝗽𝗲𝗿𝘁 𝗖𝗼𝗻𝘀𝗲𝗻𝘀𝘂𝘀
✅ Thoracic outlet syndrome (TOS) is a group of syndromes involving the compression of neurovascular structures that traverse the thoracic outlet (https://pubmed.ncbi.nlm.nih.gov/32491382/). This thoracic outlet comprises of the subclavian vein, subclavian artery, and brachial plexus passing through interscalene triangle, costoclavicular space, and retropectoralis minor space (https://pubmed.ncbi.nlm.nih.gov/39330749/).
✅ TOS has 3 clinical categories, venous, arterial, and neurogenic, and 5 subtypes, arterial vascular, venous vascular, true neurologic, traumatic neurovascular, and disputed (https://pubmed.ncbi.nlm.nih.gov/14649631/, https://pubmed.ncbi.nlm.nih.gov/39330749/). Neurogenic thoracic outlet syndrome (nTOS) is a subset of this group of syndromes caused by brachial plexus compression (https://pubmed.ncbi.nlm.nih.gov/32491382).
✅ Although TOS itself is a rare syndrome, with an incidence of 1-3 cases per 100,000, nTOS comprises 95%-99% of TOS cases and is recognized by the Society of Vascular Surgery as the primary form of TOS (https://pubmed.ncbi.nlm.nih.gov/35963513/, https://pubmed.ncbi.nlm.nih.gov/27565596/). nTOS is more common in athletes, musicians and other professions that require an increased involvement of the upper limb and commonly presents with intrinsic hand muscle atrophy, hand weakness, neurologic sensory deficits, and non-specific pain in the upper limb.
📘 Wagner et al. (https://pubmed.ncbi.nlm.nih.gov/42169800/) used an expert Delphi consensus to identify five clinically relevant criteria for distinguishing neurogenic thoracic outlet syndrome.A panel of 20 upper extremity experts rated the importance of 54 different clinical items in reference to distinguishing nTOS. Items were ranked on a scale from 0 (least important) to 10 (most important). The mean and standard deviation for each item’s rankings were calculated.
The Cronbach alpha (a) value was used to determine the degree of concordance among the panelists’ rankings. Analogous items with similarly high rankings were combined to help develop the final criteria.
💡 The 5 criteria deemed clinically important for nTOS were:
1️⃣ 𝗮 𝗽𝗼𝘀𝗶𝘁𝗶𝘃𝗲 𝗿𝗲𝘀𝗽𝗼𝗻𝘀𝗲 𝘁𝗼 𝗶𝗻𝗷𝗲𝗰𝘁𝗶𝗼𝗻𝘀 (𝗽𝗲𝗰𝘁𝗼𝗿𝗮𝗹𝗶𝘀 𝗺𝗶𝗻𝗼𝗿, 𝗮𝗻𝘁𝗲𝗿𝗶𝗼𝗿 𝘀𝗰𝗮𝗹𝗲𝗻𝗲, 𝗺𝗶𝗱𝗱𝗹𝗲 𝘀𝗰𝗮𝗹𝗲𝗻𝗲)
Symptom relief after local anesthetic injection into the pectoralis minor, anterior scalene, or middle scalene supports nTOS.
The value of this criterion is not just “pain relief” (≥ 50% of pain or paresthesia relief as a positive result) but the localization of symptom-generating compression to either the scalene region or the pectoralis-minor/retropectoralis space.
2️⃣ 𝘂𝗽𝗽𝗲𝗿 𝗼𝗿 𝗹𝗼𝘄𝗲𝗿 𝘁𝗿𝘂𝗻𝗸 𝗿𝗮𝗱𝗶𝗮𝘁𝗶𝗻𝗴 𝘀𝘆𝗺𝗽𝘁𝗼𝗺𝘀 𝘁𝗵𝗮𝘁 𝘄𝗼𝗿𝘀𝗲𝗻 𝘄𝗶𝘁𝗵 𝘀𝘂𝗽𝗿𝗮𝗰𝗹𝗮𝘃𝗶𝗰𝘂𝗹𝗮𝗿 𝗽𝗿𝗼𝘃𝗼𝗰𝗮𝘁𝗶𝘃𝗲 𝗺𝗮𝗻𝗲𝘂𝘃𝗲𝗿𝘀
Symptoms should be reproducible in the scalene/supraclavicular region, for example by scalene pressure or Tinel sign over the scalenes. This criterion reflects suspected irritation of the brachial plexus in the scalene triangle. Worsening symptoms with the neck and shoulder movements and arm pain were combined and classified as upper trunk symptoms. Furthermore, paresthesias in the fourth and fifth fingers) and weakness in the hand were categorized as lower trunk symptoms.
3️⃣ 𝘂𝗽𝗽𝗲𝗿 𝗼𝗿 𝗹𝗼𝘄𝗲𝗿 𝘁𝗿𝘂𝗻𝗸 𝘀𝘆𝗺𝗽𝘁𝗼𝗺𝘀 𝘁𝗵𝗮𝘁 𝘄𝗼𝗿𝘀𝗲𝗻 𝘄𝗶𝘁𝗵 𝗶𝗻𝗳𝗿𝗮𝗰𝗹𝗮𝘃𝗶𝗰𝘂𝗹𝗮𝗿 𝗽𝗿𝗼𝘃𝗼𝗰𝗮𝘁𝗶𝘃𝗲 𝗺𝗮𝗻𝗲𝘂𝘃𝗲𝗿𝘀
Symptoms should be reproducible medial to the coracoid or around the coracoid/pectoralis minor region, through Tinel sign or local tenderness. This points toward possible compression in the infraclavicular or retropectoralis minor space, rather than primarily between the scalenes.
4️⃣ 𝗿𝗲𝗽𝗿𝗼𝗱𝘂𝗰𝘁𝗶𝗼𝗻 𝗼𝗳 𝗽𝗮𝗶𝗻 𝘄𝗶𝘁𝗵 90° 𝗮𝗯𝗱𝘂𝗰𝘁𝗶𝗼𝗻 𝗶𝗻 𝗲𝘅𝘁𝗲𝗿𝗻𝗮𝗹 𝗿𝗼𝘁𝗮𝘁𝗶𝗼𝗻 𝗼𝗿 𝘂𝗽𝗽𝗲𝗿 𝗹𝗶𝗺𝗯 𝘁𝗲𝗻𝘀𝗶𝗼𝗻 𝘁𝗲𝘀𝘁
Symptoms reproduced with 90° abduction/external rotation and/or symptoms reproduced with the upper limb tension test suggest neural mechanosensitivity.
5️⃣ 𝗽𝗮𝗿𝘁𝗶𝗰𝗶𝗽𝗮𝘁𝗶𝗼𝗻 𝗶𝗻 𝘄𝗼𝗿𝗸/𝗲𝘅𝗲𝗿𝗰𝗶𝘀𝗲 𝗿𝗲𝗾𝘂𝗶𝗿𝗶𝗻𝗴 𝗿𝗲𝗽𝗲𝘁𝗶𝘁𝗶𝘃𝗲 𝗮𝗿𝗺 𝘀𝘁𝗿𝗲𝘀𝘀
Repetitive overhead activity, throwing, sustained protraction, or repetitive arm stress is not diagnostic on its own. It increases plausibility when the exposure matches the symptom behavior and provocation findings.
⭕ Limitations
These diagnostic criteria should be interpreted with caution. The study is based on expert consensus rather than prospective clinical validation, and there is still no universally accepted reference standard for diagnosing neurogenic thoracic outlet syndrome.
📷illustration: Overview of the structures of the thoracic outlet.
There several important features in the thoracic outlet at the base of the neck: the scalene triangle, the costoclavicular space, and the subcoracoid (pectoralis minor) space. The scalene triangle is bounded by the anterior middle scalene muscles, as well as the 1st rib. Through this space passes the brachial plexus, which is composed of five nerve roots (C5, C6, C7, C8, and T1), as well as the brachial artery. The subclavian vein passes through the costoclavicular space, anterior to the anterior scalene muscle.
📖 Wagner, E. R., Sullivan, C. M., Cuneo, K. R., Chopra, K. N., Omole, O., Gottschalk, M. B., & Bowers, R. L. (2026). Defining Diagnostic Criteria for Neurogenic Thoracic Outlet Syndrome: An Expert Consensus. Orthopaedic journal of sports medicine, 14(5), 23259671261440925. https://doi.org/10.1177/23259671261440925