Brain's Precentral Sulcus, Lateral View

Description

Precentral sulcus forms a prominent longitudinal groove on the lateral surface of the frontal lobe, positioned immediately anterior to the precentral gyrus and roughly parallel to the central sulcus posteriorly. Superiorly it approaches the superomedial margin near the paracentral lobule, while inferiorly it descends toward the lateral sulcus (Sylvian fissure) and the frontal operculum. The precentral gyrus between the precentral and central sulci carries primary motor cortex (Brodmann area 4), and the sulcal walls and adjacent gyri outline the transition into premotor and supplementary motor areas (area 6) anteriorly. Sulcal segments and bridging gyri are visible as subtle interruptions, a common anatomic variant with surgical relevance. Localizing the precentral sulcus matters because it helps bracket the central sulcus when surface anatomy is the only reference, a recurring problem during planning for convexity craniotomy, tumor resection, or subdural grid placement. Lesions involving the precentral gyrus typically produce contralateral weakness with somatotopic bias, and perirolandic infarcts in the middle cerebral artery territory often spare sensation when the postcentral gyrus is not involved. Lighting and shadowing along the lateral convexity make the depth and course of the sulcus legible, so you can distinguish precentral from the more posterior central sulcus and the more anterior superior and inferior frontal sulci. Small differences in that distinction change where you place your motor strip. It is a surface landmark that affects decisions. Use this illustration in neuroanatomy teaching on the cerebral hemispheres, in operative neurosurgical atlases to annotate the rolandic region, and in neurology publications discussing motor cortex localization for stroke, epilepsy, or transcranial magnetic stimulation targeting. Anatomical accuracy verified by SciePro's Medical Advisory Board.