Space
Cerebral aqueduct
Midbrain channel connecting the third and fourth ventricles
High-yield
Aqueductal obstruction traps fluid upstream, typically enlarging both lateral ventricles and the third ventricle while leaving the fourth ventricle relatively normal.
Overview
The cerebral aqueduct is a slender CSF passage through the midbrain. Periaqueductal gray surrounds it, with tectum behind and tegmentum in front. Unlike the larger ventricles, the aqueduct contains no choroid plexus.
Reference facts
- Boundaries
- Lined by ependyma within the midbrain and surrounded by periaqueductal gray, between the tectal and tegmental regions
- Contents
- Cerebrospinal fluid; no choroid plexus
- Communications
- Third ventricle rostrally to fourth ventricle caudally
Clinical correlation
Aqueductal narrowing can be developmental or arise from a nearby lesion. The ventricular enlargement pattern helps locate a blockage, but imaging must also assess the channel and other CSF pathways.
Frequently asked questions
What are the boundaries of the cerebral aqueduct?
The cerebral aqueduct is bounded by the lined by ependyma within the midbrain and surrounded by periaqueductal gray, between the tectal and tegmental regions.
What does the cerebral aqueduct contain?
Cerebrospinal fluid; no choroid plexus.
What does the cerebral aqueduct communicate with?
The cerebral aqueduct communicates with the third ventricle rostrally to fourth ventricle caudally.