a. Arch of thoracic duct b. External jugular vein c. Subclavian vein d. Cephalic vein e. Superior belly of omohyoid muscle f. Sternothyroid muscle g. Sternohyoid muscle h. Clavicle hed of pectoralis major muscle i. Suprascapular artery j. Sternocostal head of pectoralis major muscle k. Pectoralis minor l. External intercostal muscle (1st intercostal space) m. Thyroid cartilage n. Thyrohyoid muscle o. Deltoid muscle p. Lymphatic node q. Axillary vein r. First rib s. Clavicle