The base of the brain has cerebellar tonsils
, which in large part are responsible for our balance and coordination.
The distance from the caudal aspect of the cerebellar tonsil
to the foramen magnum line is shown (white triangle line)
The cerebellar tonsils
were not herniated or grooved.
Syringomyelia is present in 30 to 70% of CM-I patients.[1-3] The progression of syringomyelia associated with CM-I is due to the action of the cerebellar tonsils
, which partially occlude the subarachnoid space at the foramen magnum and act as a piston on the partially enclosed spinal subarachnoid space. Syringomyelia can be also associated with specific clinical signs and symptoms.
At neurological counseling electroencephalography showed bilateral delta waves with spikes and cranial MRI revealed a 7 mm herniation of the cerebellar tonsils
from the foramen magnum (Figure 1).
In cases of Chiari I Malformation, these patients have structures without signal alteration in their anatomy, although part of it (the cerebellar tonsils
) has migrated at least 5 mm towards the spinal canal.
Caption: FIGURE 1: a (left): brain CT scan showing a diffuse edema with the disappearance of the gray/white matter limitation; b (right): herniation of the cerebellar tonsils
In these cases, the caudal herniation of the cerebellar tonsils
, without neurological signs, was not associated with a significantly increased CAI.
"Position of cerebellar tonsils
in the normal population and in patients with Chiari malformation.
In CM-1, variable caudal displacement of cerebellar tonsils
occurs into the upper cervical canal.
Cranial magnetic resonance imaging (MRI) revealed that his cerebellar tonsils
extended approximately 10 mm inferiorly through the foremen magnum, which represented a type I Arnold-Chiari malformation.
1-4 show the tumor causing a pressure effect on the brain, herniation of the cerebellar tonsils
12 mm below the posterior margin of the foramen magnum and a mass effect on the brain stem with impending cerebellar herniation and brain stem compression.
(13) Chiari zero is also a controversial designation: indicating normal position of the cerebellar tonsils
on imaging studies, but clinical presentation of headache, which is reminiscent of the experiences of patients with Chiari I (personal communication, David M.
An autopsy revealed cerebral edema with herniation of the cerebellar tonsils
and brain stem compression and hypoxic encephalopathy associated with diabetic ketoacidosis.
Arnold Chiari syndrome is a condition characterized by herniation of the cerebellar tonsils
through the foramen magnum and is classified into three types according to the degree of herniation .