The Posterolateral Sulcus Of The Medulla Oblongata Of The Human Brainstem

Description

Running longitudinally along the dorsolateral medulla, the posterolateral sulcus (sulcus posterolateralis) is traced as a shallow furrow between the posterior funiculus medially and the lateral funiculus laterally. As the animation advances, the sulcus is followed from the caudal closed medulla toward the open medulla, where the floor of the fourth ventricle comes into view superiorly and the dorsal surface contours change accordingly. Nearby surface landmarks such as the posterior median sulcus and the inferolateral curvature of the medullary tegmentum help anchor orientation as the camera tracks the groove in sequence. Clinically, this sulcus matters because it marks the root entry zone for the glossopharyngeal, vagus, and cranial accessory nerves (CN IX, X, XI) as they emerge along the dorsolateral medulla, a relationship that guides interpretation of lower cranial neuropathies and surgical corridors. Lesions affecting the lateral medulla, classically posterior inferior cerebellar artery infarction (Wallenberg syndrome), produce a characteristic pattern of dysphagia, hoarseness, vertigo, and crossed sensory loss that becomes easier to localize when you can relate symptoms to surface anatomy and root entry/exit zones. Motion clarifies the continuity of this sulcus across the medullary transition from closed to open configurations in a way a single still cannot. A small groove, big consequences. Use this animation to support neuroanatomy teaching on brainstem external landmarks, to annotate figures in neurology and neuroradiology texts when correlating dorsolateral medullary strokes with clinical signs, or to orient operative planning discussions near the lower cranial nerves and vertebral artery-PICA complex at the foramen magnum. Anatomical accuracy verified by SciePro's Medical Advisory Board.