00:01
So things that can go wrong during cerebellar development include the chiari malformation.
00:06
Now, chiari malformation has a variety of subtypes but the main thing to remember
is that there´s too little space in the posterior cranial fossa.
00:14
So the cerebellum normally fits in that posterior cranial fossa very nicely
but with too little space, it has to go somewhere.
00:21
And in type I and type II chiari malformation,
the cerebellum partially herniates inferiorly through the foramen magnum.
00:30
In particular, the cerebellum tonsils tend to extend down the foramen magnum
and they put pressure on the medulla that´s located anterior to it.
00:39
Now, that pressure on the medulla can result in difficulty
with organizing your respiratory and heart activity
because your parasympathetic cardiorespiratory nucleus is located just in that area.
00:54
So this is tied to some problems with regulating breathing and heartbeat.
00:59
In addition, having that pressure can back up the flow of cerebral spinal fluid
causing hydrocephaly or even syringomyelia
which is going to be a cyst that develops in the central canal of the spinal cord
as fluid is unable to exit the central canal,
it builds up and creates a cyst in the upper cervical region.
01:19
And again, that is syringomyelia.
01:21
Now, another problem involving the cerebellum
is called Dandy-Walker Malformation.
01:26
And it´s a series of problems
that basically boil down to there being too little cerebellum.
01:32
Agenesis of the cerebellar vermis, the midline region of the cerebellum
can result in an expansion of the fourth ventricle.
01:40
If there´s no cerebellum there,
then, the space that it used to occupy will now be filled
with cerebrospinal fluid of the fourth ventricle.
01:47
And as that fluid builds up, it´s gonna cause a ballooning of the dura mater
that´s just superior to where the cerebellum´s going to be located.
01:57
So altogether, that´s known as Dandy-Walker Malformation
and this can result in post-natal hydrocephaly
and has a variety of other problems that need to be diagnosed radiologically
and this is a fairly good example
of what that´s going to look like in sagittal cross section.
02:14
Malformations of the Midbrain-Hindbrain are very rare,
but have been previously reported.
02:20
Patients present with abnormal eye movements -
due to the involvement of the oculomotor nuclei -, cranial nerve deficits -
such as dysphagia, trigeminal anesthesia or hearing loss.
02:33
Cognitive impairment and mental retardation are usual associated features.