Comprehensive review of the cerebral aqueduct: anatomy, embryology, imaging, genetics, molecular, and pathology.

The cerebral aqueduct (CA), or aqueduct of Sylvius, is the narrowest portion of the ventricular system, connecting the third and fourth ventricles and providing an essential conduit for cerebrospinal fluid (CSF) circulation. Despite its small caliber, the CA transmits over 500 ml of CSF daily, and its vulnerability to obstruction makes it central to the pathophysiology of hydrocephalus. This review synthesizes current knowledge of the CA across developmental, anatomical, and clinical dimensions. We examine its embryological formation and the contribution of structures such as the subcommissural organ and Reissner's fiber, highlighting comparative features across species, and evaluate the dynamic physiology of CSF flow in relation to age and disease states. Advances in imaging modalities, including high-resolution magnetic resonance imaging and fetal ultrasound, are summarized in the contexts of both research and clinical practice. Pathological considerations are addressed, ranging from congenital anomalies (e.g., aqueductal webs, Chiari malformations, cavernomas, and forking) to acquired lesions (e.g., gliosis, neoplasia, and trauma-induced stenosis). The genetic underpinnings of aqueductal stenosis are reviewed, emphasizing L1CAM mutations and broader molecular pathways implicated in congenital hydrocephalus. Surgical strategies, including endoscopic third ventriculostomy, aqueductoplasty, and transaqueductal stenting, are critically appraised in terms of efficacy, complication profiles, and long-term outcomes. Overall, this review underscores the CA as a nexus of neurodevelopment, neuropathology, and neurosurgical innovation, and identifies gaps in knowledge that merit future investigation.