11/26/2025
Thoracic Outlet Syndrome (TOS) is a group of conditions caused by compression of the nerves or blood vessels that pass through the thoracic outlet—the narrow space between your collarbone (clavicle) and first rib.
What gets compressed?
There are three main structures that can be affected:
1. Nerves (brachial plexus) → Neurogenic TOS (most common)
2. Arteries (subclavian artery) → Arterial TOS (rare but serious)
3. Veins (subclavian vein) → Venous TOS
Common Symptoms
Neurogenic TOS:
• Numbness or tingling in the arm, hand, or fingers
• Weakness or fatigue of the arm/hand
• Neck, shoulder, or arm pain
Venous TOS:
• Swelling or heaviness of the arm
• Bluish discoloration
• Visible chest/shoulder vein enlargement
Arterial TOS:
• Cold fingers or hand
• Pale or blue coloration
• Reduced pulses in the arm
• Pain with arm use
Typical Causes
• Poor posture (forward head, rounded shoulders)
• Repetitive overhead movements
• Trauma (car accidents, clavicle fractures)
• Anatomical variations (extra rib, tight scalene muscles)
• Weightlifting or hypertrophy of chest/shoulder muscles
Cases in which improvement can be expected with chiropractic care
Especially in cases of Neurogenic TOS, when the symptoms are caused by:
• Muscle tension in the shoulders or neck
• Poor posture (such as rounded shoulders or forward head posture)
• Reduced mobility around the clavicle or thoracic cage
Chiropractic care can often reduce symptoms through postural correction, muscle relaxation, and improving joint mobility.
Surgery may be required for severe arterial or venous TOS, or persistent neurogenic cases.
