Ultrasound image of fetus with<unk> .<unk>  can often be diagnosed before birth through an ultrasound examination. The maternal serum alpha-fetoprotein (AFP screening) and detailed fetal ultrasound can be useful for screening for neural tube defects such as spina bifida or<unk> . Meroanencephaly Meroanencephaly is a rare form of<unk>  characterized by malformed cranial bones, a median cranial defect, and a cranial protrusion called area cerebrovasculosa. Area cerebrovasculosa is a section of abnormal, spongy, vascular tissue admixed with glial tissue ranging from simply a membrane to a large mass of connective tissue, hemorrhagic vascular channels, glial nodules, and disorganized choroid plexuses. Holoanencephaly The most common type of<unk> , where the brain has entirely failed to form, except for the brain stem. Infants rarely survive more than one day after birth with holoanencephaly. Craniorachischisis The most severe type of<unk>  where area cerebrovasculosa and area medullovasculosa fill both cranial defects and the spinal column. Craniorachischisis is characterized by<unk>  accompanied by bony defects in the spine and the exposure of neural tissue as the vault of the skull fails to form. Craniorachischisis occurs in about 1 of every 1000 live births, but various physical and chemical tests can detect neural tube closure during early pregnancy.
Anencephaly
Exencephaly
Hydranencephaly
Hemihydranencephaly
Megalencephaly
Schizencephaly
Microhydranencephaly
Lissencephaly