The Mouse Adult Gross Anatomy Ontology and Mammalian Phenotype Ontology are downloaded weekly from the Mouse Genome Informatics databases at Jackson Laboratories (ftp://ftp.informatics.jax.org/pub/reports/index.html). For more information about these ontologies, see the MGI Publications Page at http://www.informatics.jax.org/mgihome/other/publications.shtml.
the luminal space of one or more of the four communicating cavities within the brain that are continuous with the central canal of the spinal cord is increased in volume or area, usually with an increase in contained fluid