Term: fourth ventricle anatomical margin
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]

Name: anatomical margin
Synonyms: edge, margin
Definition: Fiat anatomical region extending a short distance from the boundary of an object inwards.
Ontology: Spatial Ontology [BSPO:0000006]