Thoracic outlet syndrome (TOS) is a group of conditions where nerves and/or blood vessels get compressed as they pass through the space between your neck and armpit. The most common form is neurogenic TOS, affecting the brachial plexus nerves that supply your arm and hand.
Classic symptoms of neurogenic TOS
- Numbness or tingling in the arm, hand, or specific fingers (often ring and little fingers)
- Weakness or clumsiness in the hand
- Aching in the shoulder, neck, or arm
- Symptoms worse with overhead activity, carrying heavy bags, or sustained arm-out postures
- Cold, pale, or discoloured hand in vascular subtypes (much rarer)
Where the compression happens
Three common sites:
- Scalene triangle — between the anterior and middle scalene muscles
- Costoclavicular space — between the collarbone and first rib
- Pectoralis minor space — under the pec minor tendon
Common contributors
- Forward head and rounded shoulder posture
- Tight scalene, pec minor, and subclavius muscles
- Elevated first rib
- Cervical rib (extra rib) — anatomical variant
- Weak scapular stabilizers
Our treatment approach
Manual therapy — soft tissue release for scalenes, pec minor, subclavius, and levator scapulae. First rib mobilization when indicated.
Nerve gliding drills — specific exercises that mobilize the brachial plexus without irritating it.
Postural and scapular strengthening — the long-term fix. Weak lower and mid trap plus tight anterior chest keep the outlet compressed.
Ergonomic changes — workstation, sleeping position, and lifestyle modifications that reduce sustained compression.
When to seek assessment
If you've had persistent arm tingling that doesn't fit a clear cervical radiculopathy pattern, or symptoms worsen with overhead positions, come in for testing. TOS is diagnosed clinically with specific provocative tests — imaging is often normal.