Final answer:
Dandy-Walker malformation is a congenital condition affecting the cerebellum and the fourth ventricle of the brain, often including agenesis of the cerebellar vermis and potentially leading to hydrocephalus. It is diagnosed via imaging techniques such as CT or MRI.
Step-by-step explanation:
The student's question pertains to Dandy-Walker malformation, a congenital brain malformation involving the cerebellum and the fluid spaces around it. Specifically, it involves a cystic expansion of the fourth ventricle and can include agenesis (absence of development) of the cerebellar vermis. This condition is most often diagnosed with imaging techniques like CT (computed tomography) or MRI (magnetic resonance imaging). The median aperture refers to an opening from the fourth ventricle into the subarachnoid space, important in the circulation of cerebrospinal fluid. Dandy-Walker malformation may lead to complications such as hydrocephalus, where ventricles in the brain become enlarged due to excess cerebrospinal fluid, as noted in the referenced case study where MRI was used to diagnose enlarged ventricles. The metencephalon is mentioned as it develops into structures including the cerebellum, which is affected in Dandy-Walker malformation.