The postcentral sulcus is the groove that runs parallel to and behind the central sulcus on the outer side of each parietal lobe. It divides the postcentral gyrus in front of it from the rest of the parietal lobe behind: its upper part from the superior parietal lobule, its lower part from the supramarginal gyrus. [1][2][3]
Seen from the left and above: the postcentral gyrus is lit in blue, the superior parietal lobule and supramarginal gyrus in orange, on both hemispheres. The groove runs where blue meets orange; the top (axial) slice button cuts across it. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
A groove has no shape of its own; lit: the parts on either side of it. Lit: in front, the postcentral gyrus in blue; behind, the superior parietal lobule and the supramarginal gyrus in orange. The postcentral sulcus lies parallel to and behind the central sulcus and divides the postcentral gyrus in front from the rest of the parietal lobe behind: its upper part from the superior parietal lobule, its lower part from the supramarginal gyrus, the front of the inferior parietal lobule. [1][2][3]
The postcentral gyrus is bounded by the central sulcus in front, the postcentral sulcus behind and the lateral sulcus below. [4]
The superior parietal lobule is bounded in front by the upper part of the postcentral sulcus, but above the end of the groove it is usually joined to the postcentral gyrus, so near the top of the brain the two banks run into each other. [2]
The inferior parietal lobule lies behind the lower part of the postcentral sulcus; its front part, the supramarginal gyrus, arches over the upturned end of the lateral fissure and is continuous in front with the postcentral gyrus. [3]
What it does
It is a landmark for the touch strip in front of it: the postcentral gyrus holds the primary somatosensory cortex, the main sensory receiving area for touch, laid out as a map of the body called the sensory homunculus. [4]
The postcentral gyrus is made of Brodmann areas 3, 1 and 2, with area 1 on its crest; the groove separates it from the posterior parietal cortex behind. [4][5]
Behind its lower part, the supramarginal gyrus is somatosensory association cortex: it interprets touch information and takes part in sensing where the limbs are and in space. [6]
Size
The model has no shape for the postcentral sulcus, so the groove itself is not measured here. Measured from the model instead: on the left hemisphere, the stretch where the postcentral gyrus and the superior parietal lobule and the supramarginal gyrus come within 3 mm of each other fits in a box about 52 mm front to back, 49 mm top to bottom and 65 mm side to side (the box that stretch fits in, not the groove’s length along its bends or its depth). [7]
Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.
