Blood supply of the internal capsule and basal nuclei

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 partis 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 Al segment, range in number from 1 to 5 (mean, 2.2) and in diameter between 80 urn and 710 urn (average, 295 urn). 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 urn to 1,600 um (average, 750 urn) and in length between 11 mmand36mm (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 um to 1,300 um (mean, 520 um). 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 μm and 500 um (mean, 236 μm). The AChA perforators that originate from its cisternal segment, range in number from 2 to 9 (mean, 4.5) and in diameter from 90 μm to 600 μm (mean, 325 μm).