Parietal Lobe

The lobe behind the frontal lobe and superior to the temporal lobe. Extemely important in motor coordination.

The parietal lobe is limited anteriorly by the central sulcus, medially by the interhemispheric fissure, inferolaterally by the sylvian fissure and the temporo-occipital line, and posteriorly by the lateral parietotemporal sulcus.

Its two main sulci are the postcentral and the intraperietal sulci. The postcentral sulcus is very similar to the central sulcus expect for its variable continuity. The postcentral sulcus is the posterior limit of the postcentral gyrus, and in some induviduals it is double. The intra-parietal sulcus starts at the postcentral sulcus and is directed posteriorly and inferiorly toward the occipital pole. Its direction is often parallel and is 2 to 3 cm lateral to the midline.

The bottom of the intraparietal sulcus is related to both the roof the intraparietal sulcus and the occipital horn. The intraparietal sulcus divides the surface of the parietal lobe into two parts: the superior and inferior parietal lobules.The superior parietal lobule, the superomedial, and the smaller part continue as precuneus in the medial surface of the paritetal lobe.

The inferior paritetal lobule is constituted by supramarginal and the angular gyri. The supramarginal gyrus is the posterior continuation of the superior temporal sulcus and turns around the posterior ascending ramus of the sylvian fissure. The angular gyrus is the posterior continuation of the middle temporal gyrus and it turns superiorly and medially behind the posterior ramus of the sylvian fissure up to the intraparietal sulcus. In some induviduals, the angular gyrus is limited between the two posterior terminations of the superior temporal sulcus: the angular ramus and the superior occipital ramus. The postcentral sulcus, the intraparietal sulcus and the superior temporal lobule are mirror images of the precentral sulcus, the superior frontal sulcus and the superior frontal lobule. The mirror being the central sulcus.