Table 1.

Crucial anatomical spaces for the pathogenesis of TOS.

Space	Borders	Contents
Scalene triangle	Anterior: Scalenus anterior Posterior: Scalenus middle Inferior: 1st rib	Brachial plexus (trunks) Subclavian artery
Costoclavicular space	Anterior: Clavicle (or subclavicular muscle) Posterolateral: Upper board of the scapula Posteromedial: 1st rib	Brachial plexus (division) Subclavian vessels
Subcoracoid space	Anterior: Pectoralis minor muscle Superior: Coracoid process of the scapula Posterior: 2nd–4th ribs	Brachial plexus (cords) Axillary vessels