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.
The lecture Malformations in Cerebellar Development by Peter Ward, PhD is from the course Development of the Nervous System, Head, and Neck.
Chiari malformation types I and II are both characterized by the herniation of the cerebellar tonsils through which orifice of the skull?
Though there are various types of Chiari malformations, what is the common factor in their pathogenesis?
A Chiari malformation can lead to all of the following except?
Dandy-Walker malformation is associated with all of the following except?
Which of the following is false regarding malformations of the midbrain and hindbrain malformations?
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Thank you sir for keeping it simple and easy to understand!