investigations

Last reviewed 07/2023

Investigations for thoracic outlet syndrome may include:

• blood pressure:
• lower on the affected side
• variable with arm abduction

• X-ray:
• a bony cervical rib may be seen directly
• a fibrous band is indicated by an enlarged anterior tubercle of the seventh cervical vertebra
• apical lung tumour in Pancoast's syndrome

• nerve conduction / electromyography:
• distinguishes thoracic outlet syndrome from other peripheral nerve lesions

• arteriography:
• long standing compression of the subclavian artery may result in a post-stenotic dilatation
• abduction and external rotation of the shoulder may cause complete obstruction of subclavian blood flow in cases associated with a cervical rib