Medical Zebras

In an individual with Ehlers-Danlos Syndrome (EDS) and Craniospinal Instability (CSI), Cranial Settling is likely to occur. In Cranial Settling the tissues in the neck are weak, due to EDS, and the cervical bones are not held in place thus causing instability. This forces the cerebellar tonsils out of the skull into the spinal column through the small hole at the base of the skull called the foramen magnum, a phenomena called cerebellar herniation. When the cerebellar tonsils are out of place, they take up space normally allotted for the cerebral spinal fluid (CSF), the brainstem, and all the arteries and veins leading  through here to the brain. This puts pressure on the cerebellar tonsils and the brainstem which damages both structures progressively over time. The cerebellar tonsils are the lowest part of the cerebellum, which controls the sensory perception and motor control systems of the body. The brainstem controls the autonomic nervous system, or everything your body does without you having to thinking about it - heart rate, respiration, blood pressure control, etc. Damage to these systems is very serious, and can even be life-threatening. CSI may also allow the odontoid bone at the front of the neck to push backwards into the brainstem, causing even more damage to this structure. In addition to this, due to the crowding of the cerebellar tonsils, brainstem, and cranial arteries and veins, CSF flow may be impaired which deprives the brain and spinal cord of nutrients that they need. Spinal fluid continuously flows around the brain and spinal cord, bringing them essential nutrients. In an individual with cranial settling, however, there may not be enough room left at the opening of the skull for the spinal fluid to effectively flow.