FIG 2. Angiograms of the RA.

A, Superselective angiogram demonstrates collaterals between the RM and basilar system (arrow).

B, Angiogram obtained after surgical creation of the fistula between the CCA and EJV shows the extensive collateral network between the right VA (arrow 1) and ascending PA (arrow 2) on the left side. Note filling of the right ascending PA (arrow 3) and RM (arrow 4) by ipsilateral collaterals. The BA (arrow 5) has a small diameter.