<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>An irregularly shaped cavity in the rhombencephalon, between the medulla oblongata, the pons, and the isthmus in front, and the cerebellum behind. It is continuous with the central canal of the cord below and with the CEREBRAL AQUEDUCT above, and through its lateral and median apertures it communicates with the subarachnoid space.</n0:def-definition><n0:def-source>MSH2001</n0:def-source></n0:ComplexDefinition>
nci:P366
Fourth_Ventricle_of_the_Brain
nci:P90
<n0:ComplexTerm xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:term-name>Fourth Ventricle of Brain</n0:term-name><n0:term-group>SY</n0:term-group><n0:term-source>NCI</n0:term-source></n0:ComplexTerm><n0:ComplexTerm xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:term-name>Fourth Ventricle</n0:term-name><n0:term-group>SY</n0:term-group><n0:term-source>CTRM</n0:term-source></n0:ComplexTerm><n0:ComplexTerm xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:term-name>Fourth Ventricle</n0:term-name><n0:term-group>PT</n0:term-group><n0:term-source>NCI</n0:term-source></n0:ComplexTerm><n0:ComplexTerm xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:term-name>Fourth Ventricle of the Brain</n0:term-name><n0:term-group>SY</n0:term-group><n0:term-source>NCI</n0:term-source></n0:ComplexTerm><n0:ComplexTerm xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:term-name>Fourth Ventricle of Brain</n0:term-name><n0:term-group>DN</n0:term-group><n0:term-source>CTRM</n0:term-source></n0:ComplexTerm>
nci:P97
<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>A diamond-shaped cavity filled with cerebrospinal fluid within the pons extending between the obex in the caudal medulla and the aqueduct of Sylvius in the cerebellum.</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>