Illustration of the cisternal anterior choroidal artery (AChA) in the carotid and crural cisterns. The AChA is the first major branch arising from the posterolateral wall of the ICA after the origin of the posterior communicating artery (PCoA). The AChA has an initial posteromedial course in the carotid cistern and courses adjacent to the anterior segment of the uncus to reach the margin of the optic tract. The AChA crosses the optic tract from the lateral to medial direction and takes an abrupt turn at the most medial extension point of the artery to change its course posterolaterally before entering the crural cistern, in which the artery courses adjacent to the posterior segment of the uncus (A). Ant. Clin. Proc. = anterior clinoid process. In this study, the cisternal segment of the AChA is divided into pre- and postoptic parts that meet at the artery's genu (B), the most medial extension point of the artery, where the cisternal segment makes an abrupt turn after passing under the optic tract. The preoptic part of the AChA (blue, B) extends from its origin at the inferomedial side of the ICA to the artery's genu along the carotid cistern. The genu is commonly located just inferomedial to the initial part of the optic tract. The postoptic part of the cisternal segment courses within the crural cistern and extends from the genu to the inferior choroidal point. The postoptic part (green, B) is longer than the preoptic part and has more perforating arteries supplying critical deep structures. Note that the perforating arteries most often arise from the superolateral portion of the artery and course laterally along the preoptic segment, and perforators commonly arise from the inferomedial portion of the artery and course medially at the postoptic segment. Op. Chi. = optic chiasm. Figure from the article: "Microsurgical anatomy of the cisternal anterior choroidal artery with special emphasis on the preoptic and postoptic subdivisions" - Available with FREE/OPEN access at www.thejns.org #neuroscience #neurosurgery #neuro #neurosurgeryblog #neuroanatomy #neurosurgeon #neurosurgeryresident #medicalschool #medicalstudent #Repost @thejnspg ・・・
