Question
The covering of an omphalocele is derived from which of the following layers?
| A. |
Amnion |
| B. |
Chorion |
| C. |
Mesoderm |
| D. |
Endoderm |
|
Correct Answer � A Explanation |
 |
Omphalocele is a congenital defect where abdominal contents herniate into the umbilical cord and remain covered by a membrane. This defect occurs when midgut loops fail to return to the abdomen during development (around 10 weeks gestation).
– Membrane layers:
– Outer layer → Amnion (from umbilical cord surface)
– Middle layer → Wharton’s jelly (connective tissue)
– Inner layer → Peritoneum (lining abdominal organs)
Incorrect Options:
– Chorion: Extraembryonic, forms part of the placenta, not involved in omphalocele.
– Mesoderm: Gives rise to Wharton’s jelly inside, not the outer layer.
– Endoderm: Forms gut lining, not part of omphalocele membrane.
Omphalocele vs. Gastroschisis:
– Omphalocele: Covered by membrane, midline location, common anomalies (e.g., cardiac).
– Gastroschisis: No covering, right of umbilicus, anomalies rare.
Clinical relevance:
– Often associated with trisomies (13, 18, 21) & Beckwith-Wiedemann syndrome.