The Relationship Between Magnetic Resonance Imaging Findings and Postural Maneuver and Physical Examination Tests in Patients With Thoracic Outlet Syndrome: Results of a Double-Blind, Controlled Study

Sagittal-weighted image of the sagittal T1-weighted MR image of the interscalene angle and thickness of anterior scalene muscle (in millimeters). Abbreviations: a, subclavian artery; AS, thickness of anterior scalene muscle (in millimeters); p, brachial plexus; v, subclavian vein. *The interscalene angle.

Sagittal T1-weighted MR image of the thickness of the subclavius muscle (in millimeters), minimum costoclavicular distance (in millimeters), and the angle between the first rib and horizontal axis. Abbreviations: a, subclavian artery; c, clavicle; CCD, minimum costoclavicular distance (in millimeters); p, brachial plexus; SC, thickness of subclavius muscle (in millimeters); v, subclavian vein. **The angle between first rib and horizontal axis.

Sagittal T1-weighted MRI image of retropectoralis minor distance. Abbreviations: cp, coracoid process; RMD, retropectoralis minor distance (in millimeters).

Comparison of patient and control groups’ MRIs of the (A) left- and (B) right-side measures. Abbreviations: ABFRH, angle between first rib and s horizontal; CG, control group; IA, interscalene angle; MCD, minimum costoclavicular distance (mm); PG, patient group; RMD, retropectoralis minor distance (in millimeters); TASM, thickness of anterior scalene muscle (in millimeters); TSM, thickness of subclavius muscle (in millimeters).

(A) Normal view of the subclavian vascular structure and brachial plexus in costoclavicular space in the neutral position. (B) Compressions of these structures in the provocative position in sagittal T1-weighted MRI in the same patient. Abbreviations: a, subclavian artery; p, brachial plexus; v, subclavian vein.

Coronal T1-weighted image showing the left subclavian vascular structures and vertical oblique hypointense thick fibrous band that caused the distortion of brachial plexus (arrows).

In another patient, the coronal T1-weighted image showing the hypointense thin fibrous band arising from the transverse process of C7 and crossing the left subclavian artery (arrows).