Accessory middle cerebral artery originating from callosomarginal artery.

An accessory middle cerebral artery (AMCA) is a variation of the cranial vascular system. It usually originates from the anterior cerebral artery, particularly from its proximal part and supplies the orbitofrontal and prefrontal regions of the territory of the middle cerebral artery (MCA). It is reported in approximately 3% of dissections (Teal et al., 1973; Yasargil, 1984; Umansky et al., 1988; Tanriover et al., 2003). Whether an AMCA is a variant of Heubner’s recurrent artery has been debated (Takahashi et al., 1989). An associa-