Occipito Parietal Sulcus

The Occipito Parietral Sulcus (OcPS) separates the mesial parietal lobe (precuneus) from the mesial occipital lobe (cuneus). It starts at the Calcarine Sulcus and its origine is best found in coronal (1) and parasagital (2) slices (at the crossing of the orthogonal axes). [The calcarine sulcus has been traced in all images as a reference and is shown in red.] If the first point of the curve is dropped at this level, it will overlap with the calcarine sulcus (3, detail in 4). It needs to be dropped slightly higher (5, detail in 6). The sulcus moves superiorly to the superior edge of the mesial surface of the hemisphere, where the end should be marked (7), it can however continue onto the dorsolateral surface of the hemisphere. At the superior end it can apparently split into two terminal branches; however, most often the split is in reality a deep and long side branche that needs to be recognized as such and not be followed. The OcPS is usually a continuous and deep sulcus. Because it is so deep, the whole course is best seen in a surface image of the gray-white junction (8).

USC Biomedical Imaging Research Lab © 2009, designed by Dimitrios Pantazis