Sectional anatomy of the optic pathways on the coronal plane.

BACKGROUND The purpose of this study was to provide practical data for the imaging diagnosis of the optic pathways. METHODS Sectional anatomy of the optic pathways on the coronal plane was investigated on 15 sets of serial coronal sections of the head of Chinese adult cadavers and 6 sets of serial coronal magnetic resonance imaging of normal adults. RESULTS On the coronal plane, we recognized the special structures of optic pathways by 5 key sections. (1) The midorbital optic nerve lay superomedially in the center of the adipose body of the orbit, surrounded by the subarachnoid space and the sheath of the optic nerve. (2) The optic chiasma was transverse between the optic and infundibular recesses of the portion of the floor of the third ventricle and it lay below the A1 segment of the anterior cerebral artery and above the tuber cinereum and the pituitary stalk, C2 or C3 segment of the internal carotid artery laterally. (3) The optic tract lay between the crus cerebri and the amygdaloid, the tail of the caudate nucleus laterally. The anterior choroidal artery inferiorly and downward M2 segment of the middle cerebral artery lay between the uncus and the crus cerebri. (4) The lateral geniculate body lay between the crus cerebri medially and the tail of the caudate nucleus laterally, the uncus and P2 segment of the posterior cerebral artery inferiorly. (5) The optic radiation formed the lateral wall of the lateral ventricle both in the temporal horn and in the occipital horn. The optic radiation was separated from the wall of the occipital horn by the tapetum, a thin layer of fibers derived from the splenium of the corpus callosum. Coronal sectional anatomy and magnetic resonance imaging of the optic pathways revealed similar results. CONCLUSION This study provides a good understanding of the structures of the optic pathways by correlation of coronal sections of the head of adult cadavers with the coronal magnetic resonance images of normal adults.