大腦中動脈是頸內動脈在臚內的終末段，頸內動脈在此分出大腦中動脈與大腦前動脈，大腦中動脈在命名上可分為四段：M1, M2, M3, M4
M1 sphenoidal: prebifurcation and postbifurcation parts, small cortical branch before bifurcation "early branch"
M2 insular: begin with the genu (limen insulae) and end at circular sulcus of insula,
M3 opercular: begin at circular sulcus of insula and end at surface of sylvian fissure
M4 cortical branch
Lenticulostriate branches豆紋動脈: 由M1段發出, 約 1-21 分枝 (平均 10條), 80% 在分岔前發出
1. Media group: least constant, present in 50% cases, 1-5 branch, direct course into ant perforated substance
2. Intermediate group: present in 90% of cases, average 3 branches, at lease one major branch and branching
3. Lateral group: present in all cases, average 5 branches branching into 20 small branch entering posteriolateral part of ant perforated substance.
* Lateral and intermediate group supply almost entire upper part of internal capsule, body and head of the caudate nucleus. Medial group supply lateral part of globus pallidus, the superior part of anterior limb of the internal capsule, anteriosuperior part of the head of the caudate nucleus.
* 30% of the lateral group arise within 2.0 mm of pre- and postbifurcation, and 70% within 5.0 mm
The main trunk of MCA divide in 3 ways
1. Superior, inferior trunk: 78%
2. Superior, middle and inferior trunk: 12%
3. Multiple trunk:10%
Stem artery: arise from trunk and supply individual or multiple cortical artery.
Temporopolar, temporo-occipital, angular, and anterior, middle, posterior temporal artery arise from inferior trunk
Orbitofrontal, prefrontal, precentral and central arteries arise from superior trunk
Anterior and posterior parietal arteries from dominent trunk (50% vs 50%)
1. Orbitofrontal area
2. Prefrontal area
3. Precentral area
4. Central area
5. Anterior parietal area
6. Posterior parietal area
7. Angular area
8. Temporo-occipital area
9. Posterior temporal area
10. Middle temporal area
11. Anterior temporal area
12. Temporopolar area