Altered Hemodynamics Associated with Pathogenesis of the Vertebral Artery Dissecting Aneurysms

Table 1

The three types of vertebral artery with comparison of affected and nonaffected sides.

		Affected side
		Type I	Type II	Type III
Non-affected side	Type I	11 (4)	7 (0)	17 (17)
	Type II	6 (3)	1 (1)	0 (0)
	Type III	11 (4)	2 (0)	0 (0)
	None	1 (0)	0 (0)	1 (1)
	Total	29 (11)	10 (1)	18 (18)

The location of the dissection with reference to tortuous portions.
( ): just proximal to the tortuous portion.