RESUMO
The internal capsule and basal nuclei are supplied by perforating branches of the anterior cerebral artery (ACA), Heubner's artery, middle cerebral artery (MCA), internal carotid artery (ICA) and anterior choroidal artery (AChA). Some of the mentioned perforators vascularize both the internal capsule and basal nuclei, while some of them also perfuse the adjacent brain structures. Dorsal part of the anterior limb, knee and posterior limb of the internal capsule are commonly supplied by lateral MCA perforators. The intermediate part of the anterior limb is perfused by medial MCA perforators, while its ventral part is nourished by ACA perforators and Heubner's artery. The intermediate part of the knee is supplied by medial MCA perforators, while its ventral part is mostly vascularized by ICA and proximal AChA perforators. The intermediate part of the posterior limb is perfused by medial MCA perforators anteriorly and the proximal AChA perforators posteriorly. The ventral part is supplied by AChA perforators. The retrolenticular and sublenticular portions of the internal capsule are mainly nourished by distal AChA perforators. The caudate nucleus is supplied by perforators of the ACA, MCA and AChA, as well as by branches of the lateral posterior choroidal artery. Most of the putamen is vascularized by MCA perforators, and smaller parts by ACA and AChA perforators. The lateral segment of the globus pallidus is perfused by MCA perforators and partially by Heubner's artery and ACA, while its medial segment is supplied by ICA and AChA perforators. The ACA perforators, that most often originate from the initial 5.9 mm of the A1 segment, range in number from 1 to 5 (mean, 2.2) and in diameter between 80 pm and 710 pm (average, 295 microm). Heubner's artery, which most often arises close to the anterior communicating artery, can be singular (72.5%), double (23%) or triple (4.5%). It varies in diameter from 190 microm to 1,600 pm (average, 750 microm) and in length between 11 mm and 36 mm (mean, 22.4 mm). The MCA perforators, that most frequently originate from M1 segment (90.7%) and leptomeningeal branches (62.6%), range in number between 2 and 13 (mean, 8.1) and in diameter from 80 microm to 1,300 microm (mean, 520 microm). Many perforators arise as individual vessels, and some of them with common trunks (70.8%). Medial and lateral group of these perforators can be distinguished. The ICA perforators, which more often arise close to the AChA originating site (35.4%) than from the ICA bifurcation point (10.4%), vary in number from 1 to 5 (average, 3) and in diameter between 70 microm and 500 microm (mean, 236 microm). The AChA perforators that originate from its cisternal segment, range in number from 2 to 9 (mean, 4.5) and in diameter from 90 microm to 600 pm (mean, 325 microm).
