Brain's Straight Gyrus, Inferior View

Description

Gyrus rectus (straight gyrus) occupies the most medial strip of the orbital surface of the frontal lobe in this inferior view, running anteroposteriorly alongside the interhemispheric (longitudinal) fissure. Laterally, its border is defined by the olfactory sulcus, the groove that typically lodges the olfactory bulb and tract, while the more lateral orbital gyri occupy the remainder of the inferior frontal surface. Anteriorly the gyrus rectus approaches the frontal pole; posteriorly it narrows toward the region of the anterior perforated substance and basal forebrain structures that sit deeper than the cortical plane. Orientation is immediate. An inferior perspective on the gyrus rectus matters in skull base anatomy because it sits directly above the anterior cranial fossa, the cribriform plate of the ethmoid, and the olfactory apparatus, so masses along the olfactory groove (classically olfactory groove meningiomas) often displace or flatten this medial orbital cortex before patients present with anosmia or subtle frontal-lobe behavioral change. Surgeons planning a subfrontal or endonasal approach often need a mental map of the medial orbital surface to anticipate where retraction or edema will affect orbitofrontal cortex. The fixed viewpoint clarifies the relationship between the gyrus rectus, the olfactory sulcus, and the midline fissure without the distraction of superior convexity landmarks. Use this illustration in neuroanatomy teaching on the orbital gyri, in neurosurgical education for anterior cranial fossa and olfactory groove lesions, or in radiology and neuropathology publications when correlating inferior frontal surface anatomy with MRI/CT findings near the cribriform plate. Anatomical accuracy verified by SciePro's Medical Advisory Board.