Two videos, one about Exencephaly and the other about Anencephaly.

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This video shows two cases, one about Exencephaly and the other about Anencephaly.
First-trimester ultrasound findings of exencephaly include decreased size of the cranial pole compared with the chest, dorsally bulging cranial pole, irregularity of the surface of the cranium, and echogenic amniotic fluid.
Exencephaly is a rare malformation of the neural tube with a large amount of protruding brain tissue and an absence of calvarium. It is considered to be an embryological precursor of anencephaly where the facial structures and the base of the brain are always present. Most cases are stillborn.
Exencephaly is due to the failure of the anterior neuropore to close during the 4th week of embryonic development. The underlying defect is due to a failure in mesenchymal migration. In pathologic studies, the epencephalic brain is noted to be covered by a highly vascular epithelial layer.
Acrania refers to the absence of a fetal skull with freely exposed brain tissue to amniotic fluid. Acrania often results in anencephaly, and some believe it is a precursor to all cases of anencephaly. Both can be seen on ultrasound in the first trimester.
Anencephaly is a serious birth defect in which a baby is born without parts of the brain and skull.
Holoprosencephaly. The most common type of anencephaly, where the brain has entirely failed to form, except for the brain stem. Infants rarely survive more than one day after birth with holoanencephaly.
Anencephaly is when the neural tube fails to close at the base of the skull. Neural tube defects may be caused by genes passed on from both parents and by environmental factors. Some of these factors include obesity, uncontrolled diabetes in the mother, and some prescription medicines.
Anencephaly is the absence of a large part of the brain and the skull. This is a normal fetal ultrasound performed at 21 weeks gestation. The development of the brain and nervous system begins early in fetal development. Anencephaly is one of the most common neural tube defects. Neural tube defects are birth defects that affect the tissue that becomes the spinal cord and brain.
Anencephaly occurs early in the development of an unborn baby. It results when the upper part of the neural tube fails to close. The exact cause is not known. Possible causes of anencephaly include:
Environmental toxins
Low intake of folic acid by the mother during pregnancy
In nearly all fetuses with anencephaly, the movements are qualitatively abnormal: they are forceful, jerky in character, and are of large amplitude.
Anencephaly is a lethal diagnosis, incompatible with sustained life. It has been understood that if an anencephalic infant is live-born, death will soon be imminent. Several studies have reported anencephaly to be 100% lethal in the first year of life.
Anencephaly is a lethal congenital anomaly that can be detected on ultrasound as early as 11 weeks of gestation. If some amount of neural tissue is present, the condition is termed exencephaly. Polyhydramnios is usually associated with neural tube defects. No treatment option is available for anencephaly.
Anencephaly can theoretically be diagnosed as early as 8 weeks; however, it can be missed in the first trimester. There is 100% accuracy in the second trimester for this diagnosis by ultrasound. One study showed sonography alone was 97% sensitive and 100% specific in diagnosing an open neural tube defect.
By ultrasound, the appearance will resemble “Mickey Mouse ears.” Additionally, a measurement from the top of the head to the rump (crown-rump length or CRL) is significantly reduced in affected fetuses in the first trimester.
Of those fetuses with anencephaly, a small portion will die while still in the uterus (intrauterine fetal demise or stillbirth). Approximately 25% will have excessive amniotic fluid around the fetus (polyhydramnios). Polyhydramnios may cause extra stretching of the uterus resulting in preterm contractions.
An infant born with anencephaly has some or most of the brain missing. These infants are unconscious, cannot feel, and are usually blind and deaf. Infants with anencephaly are stillborn in about 75 percent of cases. Newborns who survive die within several hours, days, or weeks.
Anencephaly is when the neural tube fails to close at the base of the skull. Neural tube defects may be caused by genes passed on from both parents and by environmental factors. Some of these factors include obesity, uncontrolled diabetes in the mother, and some prescription medicines.
These findings demonstrate that anencephaly can be reliably diagnosed at the routine 10-14-week ultrasound scan, provided a specific search is made for the sonographic features for this condition.
Anencephaly is one of the most lethal congenital defects. This case report is of an anencephalic infant who lived to 28 months of life and defies current literature.
Getting enough folic acid before and during early pregnancy can help prevent neural tube defects.