• valves
  • The development of the vertebrate heart can be considered an additive process, in which additional layers of complexity have been added throughout the evolution of a simple structure (linear heart tube) in the form of modular elements (atria, ventricles, septa, and valves). (ahajournals.org)
  • posterior
  • Besides the cerebellar hypoplasia, cysts are commonly found in the posterior cranial fossa, the ventricles and the cisterna magna are dilated/enlarged, and Dandy-Walker malformation is present. (wikipedia.org)