Term: midbrain fourth ventricle
Name: midbrain
Synonyms: mesencephalon
Definition: The brain region between the forebrain anteriorly and the hindbrain posteriorly, including the tectum dorsally and the midbrain tegmentum ventrally.
Ontology: Anatomy Ontology [ZFA:0000128]

Name: fourth ventricle
Synonyms: 4th ventricle, hindbrain ventricle, rhombencephalic ventricle, rhombencephalic vesicle, ventricle IV, ventriculus rhombencephali
Definition: Fluid-filled brain cavity. Most posterior brain ventricle.
Ontology: Anatomy Ontology [ZFA:0000110]