Areas 3, 1 & 2 – Primary Somatosensory Cortex (frequently referred to as Areas 3, 1, 2 by convention)

Brodmann area (BA) 3 is subdivided into areas 3a and 3b. Where BA 1 occupies the apex of the postcentral gyrus, the rostral border of BA 3a is in the nadir of the Central sulcus and is caudally followed by BA 3b, then BA 1, with BA 2 following and ending in the nadir of the postcentral sulcus.