What is the function of cisterna magna?
The cisterna magna is located between the cerebellum and the dorsal surface of the medulla oblongata. Cerebrospinal fluid produced in the fourth ventricle drains into the cisterna magna via the lateral apertures and median aperture.
How common is mega cisterna magna?
A mega cisterna magna occurs in approximately 1% of all brains imaged postnatally, and has been associated with infarction (however this may be due to the fact that the cerebellar hemispheres are globally small following infarction), CMV infection and chromosomal abnormalities, especially trisomy 18.
Which of the following are associated with a cisterna magna that measures greater than 10 mm?
Our results suggest that isolated enlargement of the cisterna magna to more than 10 mm is associated with normal pregnancy and neonatal outcome.
What is cisterna magna in ultrasound?
Ultrasound. On antenatal ultrasound, mega cisterna magna refers to an enlarged retrocerebellar CSF space: usually >10 mm (some consider up to 12 mm within normal limits) septa may be seen within a mega cisterna magna, which are thought to be Blake pouch vestigial remnants.
What are the radiographic features of a mega cisterna magna?
Radiographic features. Ultrasound. In antenates, mega cisterna magna refers to an enlarged retrocerebellar CSF space: usually >10 mm in antenatal imaging (some consider up to 12 mm within normal limits) septa may be seen within a mega cisterna magna, which are thought to be Blake pouch vestigial remnants 3.
Is the cerebellar vermis normal in a mega cisterna magna?
The cerebellar vermis and fourth ventricle are normal. Findings are consistent with a mega cisterna magna (MCM). It is a normal variant and corresponds to a focal enlargement of subarachnoid space in the posterior and inferior midline posterior fossa.
What causes mega cisterna magna and Blake pouch cyst?
Some authors have proposed that mega cisterna magna is a result of a delayed Blake pouch fenestration; when fenestration does not occur, it results in a Blake pouch cyst 6.
Which is larger a mega cisterna or an arachnoid cyst?
As shown in Fig.7 vascular structures next to, or in the enlarged CSF space favors a mega cisterna magna over an arachnoid cyst, due to the fact that an arachnoid cyst is a CSF filled sac that contains no vascular structures inside.