Embryological congenital anomalies
Heart
1. Total Anomalous Pulmonary Venous Return (TAPVR): blood from
pulmonary veins goes into SVC. Causes mixing of deoxygenated and oxygenated
blood. Atrial septal defect leading to shunt of blood from R. atrium to L. atrium.
2. Atrial Septal Defects: from either excessive resorption of septum primum
leading to a large oval foramen or from absence of septum secundum. Leads to L.
to R. shunting of blood.
3. Common atrium: absence of both septum primum and secundum leading to only
one atrium.
4. Ventricular Septal defect: most common and can be fixed. Part of
interventricular septum (usually membranous portion) fails to grow. Allows blood
from L. ventricle to go into both aorta and pulmonary arteries.
5. Patent Ductus Arteriosus: ductus arteriosus fails to close and form ligamentum
arteriosum. Blood from higher pressured aorta back flows into pulmonary arteries.
6. Persistent Truncus arteriosus: failure of conotruncal cushions to separate aorta
and pulmonary arteries. Single outflow trunk causing mixing of blood leading to
cyanosis.
7. Transposition of Great Arteries: R. ventricle connected to aorta and L. ventricle
connected to pulmonary artery. 2 independent circulations. Also have patent
ductus arteriosus.
8. Teratology of Fallot:
a. pulmonary stenosis
b. membraneous IV septal defect
c. overriding aorta; part of aorta is over R. ventricle
d. hypertrophy of R. ventricle
Limb development
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7.
Amelia: absence of an extremity
Meromelia: absence of part of an extremity
Phocomelia: no long bone in limbs
Syndactyly: webbed or fused digits because apoptosis fails to occur
Polydactyly: extra digits
Lobster claw: abnormal cleft between 2nd and 4th metacarpals
club foot deformations: abnormal rotation of extremities
GI Tract
1. Cleft palate: failure of palates to fuse
2. Cleft lip: failure of maxillary and nasal prominence to fuse
3. Tracheoesophageal fistula: improper division leading to open communication
between trachea and esophagus
4. Esophageal atresia: esophagus ends in blind pouch. Usually accompanied by
tracheoesophageal fistula. Associated with polyhydramnios
5. Polyhydramnios: fetus is unable to swallow amniotic fluid because of GI tract
blockage. Fluid accumulates in amniotic sac.
6. Pyloric stenosis: muscle layer in pyloric region hypertrophies, causing narrowing
of pyloric lumen.
7. Diaphragmatic Hernia: abdominal contents herniate into pleural cavity because
of failure of pleuroperitoneal membrane to fuse. Most found on left side.
Abdominal contents compress lung buds causing pulmonary hypoplasia.
8. Annular Pancreas: ventral bud fuses dorsally and ventrally with dorsal bud,
forming a ring of pancreatic tissue around duodenum.
9. Ectopic pancreas: pancreatic tissue appearing in GI tract
10. Duodenal atresia: no recanalization of duodenum causing a back up in stomach
and polyhydramnios
11. Choledochal Cyst: localized cystic dilation of biliary tree
12. Biliary atresia: some aspect of biliary tree is obliterated as a result of incomplete
recanalization. Leads to jaundice and liver failure
13. Volvulus: twisting of intestines causing loss of blood supply and bowel
obstruction
14. Omphalocele: intestinal midgut loop fails to return to abdominal cavity. Defect in
midline
15. Gastroschisis: hole in abdominal cavity lateral to midline with intestines
protruding without membranous structure covering it.
16. Meckel’s diverticulum: remnant of vitelline duct persists and forms outpouching
from ileum and connects to umbilicus via vitelline ligament.
17. Vitelline fistula: vitelline duct remains open with direct connection between
bowels and anterior surface. Fecal discharge at umbilicus occurs
18. Imperforate anus: anal membrane fails to perforate. No meconium passed
19. Bowel atresia: blind gut pouch
20. Persistent cloaca: common tube for anorectal and urogenital septum
21. Rectovaginal fistula: incomplete separation between rectum and vagina. Allows
stool to come out of vagina.