Suprapineal recess
The suprapineal recess is an anatomical structure in the ventricular system of the brain. It is located in the posterior part of the third ventricle, overlying the cerebral aqueduct.
In severe cases of hydrocephalus with increased pressure, this structure can dilate causing mass effect on the midbrain resulting in Parinaud's syndrome with bilateral inward and downward deviation of the eyes.