Atrium Of The Lateral Ventricle Of The Brain, Anatomy

Description

Atrium (trigone) of the lateral ventricle occupies the junction where the body of the ventricle expands posteriorly into the occipital horn and curves inferiorly toward the temporal (inferior) horn. Along the inferolateral floor, the collateral trigone appears as a triangular eminence produced by the collateral sulcus of the temporal lobe, positioned lateral to the ventricular cavity and inferior to the splenium-adjacent roof. Medially, the atrial cavity lies close to the midline structures of the posterior cerebrum, while laterally it approaches deep parietotemporal white matter. Boundaries read as a spatial crossroads. Anatomically, the atrium matters because it is a common site where the choroid plexus enlarges into the glomus, a frequent pitfall on CT and MRI when physiologic calcification is mistaken for hemorrhage or a mass. Pathology also localizes here: intraventricular hemorrhage can layer within the atrial recesses, and obstructive hydrocephalus may distend the ventricular system with early widening at the trigone. Neurosurgical corridors to the atrium (parietal transcortical, posterior interhemispheric, or temporal approaches) are planned around these fixed relationships, and this illustration emphasizes the collateral trigone as a floor landmark that helps orient the viewer to the occipital and temporal extensions without needing external cortical cues. Orientation is immediate. Use this illustration in neuroanatomy and neuroradiology teaching to anchor the terminology of atrium, trigone, and collateral trigone, and to support figure plates for manuscripts on hydrocephalus, intraventricular hemorrhage, or atrial choroid plexus lesions. It also suits operative anatomy sections discussing safe entry zones to the atrium relative to parietotemporal white matter and posterior ventricular landmarks. Anatomical accuracy verified by SciePro's Medical Advisory Board.