You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Tectal breaking is seen in and explain in detail?
The normal tectum has a rounded or, sometimes, a squared appearance of the colliculi and a sho cranial-caudal length. In the Chiari II malformation, variable degrees of fusion of the colliculi and upward deflection of the tectum result in prominent beaking and elongation of the tectum.Arnold Chiari malformation consists of a downward displacement of the cerebellar tonsils through the foramen magnum resulting in obstructive hydrocephalus.Dandy-Walker malformation is characterized by agenesis or hypoplasia of the cerebellar vermis, cystic dilatation of the fouh ventricle, and enlargement of the posterior fossa.