Developmental Anomalies

Question 0

Dandy-walker malformation

Answer 0

• congenital failure of cerebellar vermis to develop

- presents as a massively dilated 4th ventricle with absent cerebellum

Question 1

Cerebral aqueduct stenosis

Answer 1

• stenosis of the channel that drains CSF from 3rd to 4th ventricle
• most common cause of hydrocephalus in newborns
• presents with enlarging head circumference due to dilation of ventricles

Question 2

Arnold-chiari malformation type II

Answer 2

• congenital extension of cerebellar tonsils through foramen magnum
• obstruction of CSF flow leads to hydrocephalus
• may occur in association with meningomyocele and syringomyelia