Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Chiari malformation type 2 ?
    ### Response:
    Chiari malformation type 2 (CM type II) is a type of Chiari malformation in which both the cerebellum and brain stem tissue extend into the foramen magnum (the hole at the skull base for passing of the spinal cord). This form is often accompanied by a type of spina bifida called myelomeningocele, and can also be accompanied by syringomyelia, hydrocephalus, or other abnormalities.
    