The postcentral gyrus is a strip of cortex at the front edge of each parietal lobe: it runs from the top of the head down the side of the brain, just behind the central sulcus, and holds the primary somatosensory cortex, the main area for the sense of touch. [1]
The 3D brain needs JavaScript. The text below still says where the postcentral gyrus is and what it does.
Slice
Opens cut by a top (axial) slice through the postcentral gyrus. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
Takes part in: movement, touch — see every part of each lit together.
Where it is
A prominent gyrus on the outer (lateral) surface of the parietal lobe, the first fold behind the central sulcus. [1]
Its borders: the central sulcus in front, the postcentral sulcus behind, the lateral sulcus (Sylvian fissure) below and the longitudinal fissure, the gap between the hemispheres, at its top inner edge. [1]
The precentral gyrus, the motor strip, lies directly in front of it across the central sulcus. [2]
What it does
It is the location of the primary somatosensory cortex, the main receiving area for the sense of touch. [1][3]
OpenStax: somatosensory signals are first processed here, and this is where conscious perception of the stimulus occurs. [4]
The body is mapped along it upside down (the sensory homunculus): the toes at the top of the hemisphere, the mouth at the bottom. Lips and hands get more cortex than their size suggests, because the area given to a body part follows how densely it is packed with touch receptors, not its surface area. [3]
Each hemisphere holds a touch map of the opposite side of the body only. [3]
Connections
Its main input comes from the thalamus: sensory fibres run from the thalamus to the postcentral gyrus through the back part of the posterior limb of the internal capsule. [5]
Of its subdivisions, area 3 receives the bulk of the thalamocortical projections, which is why some researchers reserve the name “primary somatosensory cortex” for area 3 alone. [3]
Inside it
It is made of Brodmann areas 3, 1 and 2, in that order from front to back; area 3 is split into 3a and 3b, and area 1 sits on the crest of the gyrus. [1][3]
Other names
Primary somatosensory cortex or S1 (strictly the cortex it holds); sensory strip; Brodmann areas 3, 1 and 2. [3]
Size
On this model the left postcentral gyrus measures about 64 mm front to back, 60 mm top to bottom and 67 mm side to side (the box it fits in, not its volume); the right one is its mirror image. [6]
Centre of the left postcentral gyrus compared with the centre of the left precentral gyrus: 15 mm further back; 15 mm apart in a straight line. [6]
Centre of the left postcentral gyrus compared with the centre of the left thalamus: 21 mm further back, 41 mm higher, 22 mm further from the midline; 51 mm apart in a straight line. [6]
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.