Radiological Anatomy, Variations, and Clinical Significance of Septum Pellucidum: A Mini-Review

Abstract

The septum pellucidum is a thin, translucent double-membrane structure located between the anterior horns of the lateral ventricles. This mini-review explores the gross and radiological anatomy, variations, and clinical significance of the septum pellucidum. The article elaborates on the different types of variations, including cavum septum pellucidum (CSP), cavum vergae (CV), and cavum veli interpositi (CVI). The CSP is a fluid-filled pocket located within the two leaflets of the SP. It forms during fetal development and gradually obliterates before birth. However, the fusion may be prolonged or persist into adulthood in some individuals. The CV is formed when the two commissural plates fail to fuse completely during foetal development. When associated with CSP, the CV is collectively known as the cavum septum pellucidum et vergae (CSPV). However, the isolated CV is rare. The CVI is a CSF-filled space between two tela choroidea layers and communicates with the quadrigeminal cistern, superior to the pineal gland. This article discusses the radiological features of these variations using imaging techniques such as ultrasound, magnetic resonance imaging (MRI), and computed tomography (CT). Ultrasonography is particularly useful for evaluating the SP in fetuses and infants, while MRI and CT scans provide detailed visualisation of the SP and its variations. The SP has the potential to be associated with cerebral anomalies, hydrocephalus, mental disorders, and neurological symptoms. Knowing the related anatomy and detecting variations using imaging modalities are crucial for accurately diagnosing and managing these conditions.