The Mid-Fusiform Sulcus (sulcus sagittalis gyri fusiformis)

In the human brain, the mid-fusiform sulcus (MFS; sulcus sagittalis gyri fusiformis) divides the fusiform gyrus (FG) into lateral and medial partitions. Recent studies show that the MFS is identifiable in every hemisphere and is a landmark that identifies (a) cytoarchitectonic transitions among four areas of the FG, (b) functional transitions in many large-scale maps, and (c) the location of fine-scale functional regions. Thus, simply identifying the MFS in a person's brain provides researchers with knowledge regarding: (a) how cells are organized across layers within a particular cortical location, (b) how functional representations will be laid out in cortex, and (c) the precise location of functional regions from cortical folding alone. The predictive power of the MFS can guide future studies examining the anatomical-functional organization of the FG, as well as the development of translational applications for different patient populations. Nevertheless, progress has been slow in incorporating the MFS into the broader anatomical community and into neuroanatomical reference sources. For example, even though the MFS is a rare structural-functional landmark in human association cortex as just described, it is not recognized in the recently published Terminologia Neuroanatomica (TNA). In this review, I collate the anatomical and functional details of the MFS in one place for the first time. Together, this article serves as a comprehensive reference regarding the anatomical and functional details of the MFS, as well as provides a growing number of reasons to include the MFS as a recognized neuroanatomical structure in future revisions of the TNA. Anat Rec, 302:1491-1503, 2019. © 2018 American Association for Anatomy.