Sylvian temporal AVM. This AVM (Spetzler-Martin Grade III-, supplementary Grade III) is located on the sylvian surface of the temporal lobe, facing the sylvian fissure (A), as seen on an axial T1-weighted MRI study. The AVM is supplied by insular branches of the MCA, as seen on DSAs (left ICA injection; lateral [B] and anteroposterior [C] views). Left pterional cra-niotomy and wide splitting of the sylvian fissure exposed the MCA trifurcation and the arterialized vein beneath (D). By following the vein into the planum polare of the temporal lobe, the nidus was identified and circumdissected lateral to the inferior trunk, sparing the insula and frontal lobe.