03/23/2026
Structural Shift of the Neck can pull/stretch nerves going the arm.
It's why MOST symptoms lack the characteristic signs of compression - because most issues are NOT a "pinched nerve" - but are in fact stretch injuries.
Experience the Structural Difference at Foundation Chiropractic
This image brings together the full pathway of compression—from the cervical spine to the hand—and explains why symptoms don’t stay local but radiate distally. The key structure here is the brachial plexus (C5–T1), which forms roots → trunks → divisions → cords → terminal nerves. Any restriction along this path can alter neural conduction, blood flow, and movement.
At the interscalene triangle (between anterior and middle scalenes), the roots and trunks are most vulnerable. Tight scalenes—often due to forward head posture, accessory breathing, or chronic neck loading—compress especially the lower trunk (C8–T1). This explains numbness along the ulnar side of the hand (ring and little finger), a very common presentation in TOS.
As the plexus continues, it passes through the costoclavicular space—between the clavicle and first rib—along with the subclavian artery and vein. Here, scapular depression, heavy backpacks, or poor shoulder mechanics reduce the vertical space. This zone is more dynamic, meaning symptoms often worsen with shoulder retraction or carrying loads.
Further anteriorly, beneath the pectoralis minor, lies the subcoracoid (retro-pec minor) space. Tightness of pec minor—common in rounded shoulder posture—pulls the scapula into anterior tilt and protraction, narrowing this tunnel. This is a major site for neurovascular compression during overhead activities, explaining why athletes or desk workers often feel symptoms with arm elevation.
Neurologically, symptoms depend on which fibers are compressed.
Compression of the lower plexus (C8–T1) produces ulnar distribution symptoms—numbness, tingling, grip weakness.
Compression involving upper/middle trunks (C5–C7) may lead to pain or paresthesia in the lateral arm, forearm, or thumb-index region.
Chronic compression can even cause motor deficits, such as intrinsic hand muscle weakness or reduced dexterity.
Vascular involvement adds another layer. Compression of the subclavian artery can cause coldness, pallor, or fatigue in the limb, while venous compression may lead to heaviness, swelling, or discoloration—especially after activity.
Biomechanically, this entire system behaves like a dynamic tunnel influenced by posture and movement.
A forward head increases scalene tone.
Thoracic kyphosis alters rib positioning.
Scapular dyskinesis reduces subclavian and subcoracoid space.
Breathing patterns (apical vs diaphragmatic) further modulate tension in the neck and rib cage.
That’s why TOS is rarely solved by local treatment alone. It requires restoring:
– Cervical alignment
– Rib cage mechanics
– Scapular control
– Soft tissue balance (scalenes, pec minor, upper traps)
– Neurodynamic mobility
👉 The symptoms are distal, but the problem is proximal—and multi-factorial.
