Thoracic outlet syndrome investigations can be categorized into three types: the upper extremity abductor test, the Adson or oblique muscle test, and ulnar nerve conduction velocity measurement.
1. Upper extremity abduction test: upper extremity abduction 90°, 135° and 180°, hand external rotation, neck flexion and extension booth. If the subclavian neurovascular bundle is tightly pressed below the pectoralis minor stop and at the interspace between the clavicle and the first rib, pain in the neck, shoulder, and upper extremity can be felt or intensified. Radial artery pulsation is weakened or absent, blood pressure drops, and a systolic murmur is heard in the subclavian artery region.
2. Adson or oblique muscle test: This is performed under the radial artery pulsation. The patient inhales deeply, extends the neck, and turns the jaw to the examined side. If the radial artery pulsation weakens or disappears, it is a positive finding.
3. Measurement of ulnar nerve conduction velocity: Determine the conduction velocity of the ulnar nerve at the thoracic outlet, elbow and forearm, and compare it with the normal value.
The specific operation should be carried out under the guidance of specialized physicians to avoid unnecessary injuries.