Aqueduct Of The Midbrain Of The Ventricles (Posterior View)

Description

Cerebral aqueduct (aqueduct of Sylvius) sits on the midline of the mesencephalon, coursing inferiorly from the third ventricle to the fourth ventricle within the ventricular system. From a posterior perspective, the aqueduct lies deep to the tectum, positioned anterior to the superior and inferior colliculi and surrounded circumferentially by the periaqueductal gray. Superiorly it approaches the region of the pineal recess and posterior commissure, while inferiorly it aligns with the rostral roof of the fourth ventricle at the level of the isthmus. Small space, high stakes. Aqueductal caliber is a frequent bottleneck in CSF circulation, and even minor narrowing can produce obstructive hydrocephalus with upstream dilation of the lateral and third ventricles while the fourth ventricle remains relatively normal in size. This illustration is well suited for teaching why tectal plate gliomas, pineal region masses, or congenital aqueductal stenosis present with headache, papilledema, and sometimes dorsal midbrain (Parinaud) signs, given the aqueduct’s tight relationship to the quadrigeminal plate and posterior commissural region. The fixed posterior view makes it easier to orient the aqueduct against the dorsal midbrain landmarks that neurosurgeons and radiologists use when discussing the pineal region and the tectal corridor. Use this illustration in neuroanatomy lectures on the ventricular system, in neuroradiology texts explaining noncommunicating hydrocephalus patterns, or in neurosurgical education when introducing endoscopic third ventriculostomy as an alternative to shunting for aqueductal obstruction. Anatomical accuracy verified by SciePro's Medical Advisory Board.