Thoracic Outlet Syndrome: Why Neck, Rib, and Nerve Mechanics Affect Arm Symptoms

Thoracic Outlet Syndrome (TOS) is one of the most confusing conditions people search for - and one of the most misunderstood.

Symptoms include arm heaviness, tingling, numbness, weakness, or sw

elling that worsens with certain positions.

The underlying issue isn’t just a “compressed nerve.”

It’s a systems problem involving position, control, tension, and circulation.

Who This Is For

- People with arm tingling when sitting, driving, or overhead lifting

- Those diagnosed with TOS, cervical radiculopathy, or nerve irritation

- Anyone whose symptoms improve with posture changes

- Clinicians wanting a simple explanation for a very complex condition

The Big Picture (Plain Language)

The thoracic outlet is the narrow space between your collarbone and first rib where nerves and blood vessels travel into the arm.

Symptoms occur when:

- Space decreases

- Tension increases

- Blood flow reduces

- Nerves become sensitised

This is rarely due to a single tight muscle.

It’s usually a combination of posture, fatigue, breathing mechanics, and neural irritability.

The Deeper Layer (Anatomy, Physiology, Control)

Key contributors include:

- Elevated first rib

- Tight scalenes or pec minor

- Forward-head posture

- Weak scapular stabilisers

- Restricted rib mobility

- High sympathetic tone (“fight or flight”)

- Neural sensitivity

Irritated nerves become more reactive to stretch, compression, and prolonged positions.

What Effective Rehab Targets

1. Rib and upper thoracic mobility

The first rib must move for the outlet to open.

2. Scapular mechanics

Upward rotation reduces load on the brachial plexus.

3. Breathing pattern retraining

Diaphragmatic breathing reduces scalene overuse.

4. Nerve gliding (not stretching)

Restores mobility without provoking symptoms.

5. Autonomic nervous system regulation

Stress amplifies symptoms.

What We Do at Biokinetics

We assess:

- First rib position

- Scapular rhythm under load

- Neck and thoracic mechanics

- Neural tension vs irritability

- Breathing and postural endurance

Our goal is not to “stretch everything,” but to restore efficient space, movement, and nerve mobility.

Closing Reflection

TOS isn’t a simple compression problem - it’s a systems problem.

And with the right approach, it’s highly treatable.

Biokinetics uses targeted mobility, strength, neural desensitisation, and breathing techniques to restore arm comfort and control.