Grade	Injury Description	AIS-90
I	Intercostal artery/vein	2-3
	Internal mammary artery/vein	2-3
	Bronchial artery/vein	2-3
	Oesophageal artery/vein	2-3
	Hemiazygous vein	2-3
	Unnamed artery/vein	2-3
II	Azygous vein	2-3
	Internal jugular vein	2-3
	Subclavian vein	3-4
	Innominate vein	3-4
III	Carotid artery	3-5
	Innominate artery	3-4
	Subclavian artery	3-4
IV	Thoracic aorta, descending	4-5
	Inferior vena cava (intrathoracic)	3-4
	Pulmonary artery, primary intraparenchymal branch	3
	Pulmonary vein, primary intraparenchymal branch	3
V	Thoracic aorta, ascending and arch	5
	Superior vena cava	3-4
	Pulmonary artery, main trunk	4
	Pulmonary vein, main trunk	4
VI	Uncontained total transection of thoracic aorta	5
	Uncontained total transection of pulmonary hilum	4
Advance one grade for multiple grade III or IV if >50% circumference. Decrease one grade for grade IV & V if <25% circumference.