lateral lenticulostriate arteries
The lateral lenticulostriate arteries arise from the proximal middle cerebral artery (MCA), usually from M1 segment, more rarely from the postbifurcation or M2 segment. They supply the lateral portion of the putamen and external capsule as well as the upper internal capsule.
They are longer (almost twice the diameter) and more numerous than the medial lenticulostriate arteries, which arise more proximally, originating from A1 ACA segment.
Some confusion may arise when discussing the lenticulostriate arteries origin, as some, including Osborne , divide them in those that arise from the M1 segment into medial (those arising proximally) and lateral (those arising more distally) groups.