Table.

Summary of Yakes classification system for arteriovenous malformations

Yakes classification	Description
I	Arteriovenous fistula without intervening nidus, with one inflow artery and one outflow vein
II	Arteriovenous malformation with poorly differentiated nidus with multiple contributory arteries and (a) multiple outflow veins, which can be aneurysmal or (b) a solitary aneurysmal outflow vein
III	Arteriovenous malformation without a nidus, containing multiple contributory arteries and arterioles connecting directly into an aneurysmal vein and (a) one solitary outflow vein or (b) multiple outflow veins
IV	Arteriovenous malformation with nidus containing a large number of arterioles shunting into many venules, with extensive tissue infiltration