Middle Cerebral Artery Segments

The Middle Cerebral Artery is divided into M1, M2, M3 and M4 segments:

M1 segment of the middle cerebral artery.

M2 segment of the middle cerebral artery.

M3 segment of the middle cerebral artery.

M4 segment of the middle cerebral artery.

It is worth emphasizing that the nomenclature ‘M’ that designates the segments in which the middle cerebral artery is divided –proximal, pre-bifurcation: M1; post-bifurcation: M2, and beyond: M3 and M4, is derived from an angiographic study with anatomical correlation carried out by a Uruguayan neuroradiologist (Prof. Nestor Azambuja), who divided the artery in the segments whose denomination is used worldwide nowadays. As they were described in Montevideo (Uruguay), he used the first letter of the city where he developed his study. Since it coincides with “media” (middle, in English) named thus after the middle cerebral artery, the nomenclature was extended to the anterior cerebral artery, and in this case it is referred to as segment A1…

Ture et al., proposed the M5 segment, being the terminal segment. M4 and M5 segments give rise to orbitofrontal, prefrontal, precentral, central, anterior parietal, posterior parietal, angular, temporo‐occipital, posterior temporal, middle temporal, anterior temporal, and temporal polar arteries ¹⁾.