Thoracic outlet syndrome is often associated with acquired changes in anatomy that contribute, either directly or indirectly, to compression of the neurovascular structures.

These changes may be due to direct trauma, resulting in:

  • Fractures of the first rib or clavicle
  • Soft tissues changes in the thoracic outlet as a result of
    • Previous stretch injury
    • Chronic muscle strain
    • Repetitive overuse
  • Soft tissue changes due to the healing response (scarring and fibrosis)