Question

What is brain stem compression

Answer 1

This is when there is pressure exerted on the brain stem and at times on the cervical end of the spinal cord as well. The brain stem compression causes obstruction of the flow of the cerebrospinal fluid.

Answer 2

During the process of  tonsillar herniation which also known as downward cerebellar herniation or coning , the cerebellar tonsils move downward through the foramen magnum  which possibly causing compression of the lower brain stem  & upper cervical spinal cord because  they pass through the foramen magnum.