Illustration showing clip placement to avoid compromising the anterior choroidal artery (AChA) origin : If the AChA arises inferior to the aneurysm, a clip is applied perpendicular to the axis of the ICA. The proximal blade of the clip is positioned a small distance away from the origin of the AChA so as not to constrict the AChA origin, while the distal blade is positioned nuzzled close to the ICA. When the AChA arises posterior to the aneurysm base, the AChA origin is visualized by gentle compression of the aneurysm. A straight clip is then applied across the neck of the aneurysm perpendicular to the axis of the ICA, being tilted laterally away from the origin of the AChA.