Triangle of the vertebral artery Triangle of the vertebral a Boundary 1-Scalenus ant.(lat) 2-Longus colli(med. 3-Subclavian a.(inf Contents: ● Thoracic duct ● Vagus n ● Supraclavicular In ● Thyrocervical trunk ● Vertebral a. oInt thoracic a O Cervical part of sympathetic trunkTriangle of the vertebral a. Boundary 1-Scalenus ant. (lat.) 2-Longus colli. (med.) 3-Subclavian a. (inf.). Contents: Thoracic duct Vagus n. Supraclavicular ln. Thyrocervical trunk Vertebral a. Int.thoracic a. Cervical part of sympathetic trunk. Triangle of the vertebral artery 1 3 2