Superior Temporal Sulcus with Upper Branch

The Superior Temporal Sulcus (STS) separates the superior temporal gyrus from the middle temporal gyrus. It is, after the SF, the most visible sulcus on the lateral surface of the temporal lobe. It is a long sulcus that starts close, or at, the temporal pole. It has a horizontal antero-posterior course, more or less parallel to the SF. Close to the end of the SF it usually splits into two rami, one ascending the other either descending (or horizontal). The level of the split is variable among subjects. For the purpose of brain alignment we will consider the superior split as the continuation of the STS.

The first point is dropped at the anterior end (1) and from there the curve continues posteriorly (2, 3), and into the parietal lobe until the posterior end of the superior ramus (4).

The STS can be a continuous sulcus or have multiple partial interruptions. It can also be interrupted in its course by actual gyri. This happens often at the level of the split (3, 4).

•  inferior ramus

The inferior ramus can join the main portion or be seprated by a small gyrus. It is extremely variable in position length and even direction, an example is provided below (5, 6). Because it is so variable it is best left out for alignment purposes.

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