what are the tonsils of the brain
A Type I Chiari malformation is a congenital anomaly of the brain in which the cerebellar tonsils are elongated and pushed down through the opening of the base of the skull (see foramen magnum), blocking the flow of cerebrospinal fluid (CSF) as it exits through the medial and lateral apertures of the fourth ventricle. Type I Chiari malformation is a congenital anomaly of the brain in which the cerebellar tonsils are elongated and pushed down through the opening of the base of the skull (see foramen magnum), blocking the flow of cerebrospinal fluid (CSF) as it exits through the medial and lateral apertures of the fourth ventricle.