AskOrtho

THORACIC OUTLET SYNDROME (TOS)
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TOS are a group of syndromes involving pressure on the brachial plexus.
Each syndrome is named according the structure that is causing the compression.
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1️⃣ANTERIOR SCALENE SYNDROME:
The fibres of the brachial plexus must pass through a narrow aperture between scalenes anterior and medius. Any increased tone in one of these muscles (usually anterior), will provide enough compression to produce symptoms. Scarring and adhesions from injuries can be causes of compression, particularly if found at the attachments of the scalenes. Dysfunction or misalignent of the cervical/thoracic spine may also be a contributing factor to this syndrome.
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2️⃣COSTOCLAVICULAR SYNDROME:
Symptoms result in this case when the neurovascular bundle is tractioned between the clavicle and the first rib. This is often bilateral, indicating a symmetrical postural cause.
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3️⃣⃣PECTORALIS MINOR SYNDROME: In this case, the compression occurs where the neurovascular bundle passes between the tendon of pectoralis minor and the coracoid process of the scapula. Tractioning is greatest with the arm in abduction, but even with the arm dependent, enough pressure from postural problems or tight pectoralis muscles can cause symptoms.
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TOS can also compress the subclavian/axillary artery and/or vein.
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CAUSES:
Crutch use, joint subluxation, adhesions and scarring, muscular hypertonicity from postural dysfunction, trigger points, occupational stresses, emotion stresses, all of which lead to shallow breathing and poor sleeping posture.
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SIGNS AND SYMPTOMS:
All thoracic outlet syndromes feature paraesthesia in the arm, forearm, hand, and fingers. Symptoms are usually unilateral, but can be bilateral, particularly if postural dysfunction is a main cause.
Anterior scalene syndrome is also noted for edema in the hands and fingers.