The congenital defect characterized by the extrusion of abdominal contents through a defect in the abdominal wall, typically lateral to the umbilicus, and without a covering sac, is Gastroschisis.

- Gastroschisis is a full-thickness defect of the abdominal wall, usually located to the right of the umbilicus. It results in the protrusion of intestines and sometimes other abdominal organs directly into the amniotic cavity without a protective sac. This exposure can lead to inflammation and thickening of the bowel loops after birth.

- In contrast, Omphalocele involves the herniation of abdominal contents through the umbilical ring and is characterized by the presence of a membranous sac covering the protruding organs. Omphalocele is often associated with other congenital anomalies and chromosomal abnormalities.

- An Umbilical hernia is a defect within the linea alba at the site of the umbilicus where abdominal contents protrude but are covered by skin and fascia. It is usually smaller and less severe than gastroschisis or omphalocele.

- Diaphragmatic hernia refers to a defect in the diaphragm, allowing abdominal contents to herniate into the thoracic cavity, which primarily affects lung development and function but is not related to defects in the abdominal wall itself.

Key points to remember:
- Location: Gastroschisis is lateral to the umbilicus, commonly on the right side.
- Covering sac: Abdominal contents in gastroschisis are not covered by any membrane.
- Associated anomalies: Gastroschisis is usually an isolated defect; omphalocele often occurs with other anomalies.
- Clinical implications: Exposure of the bowel to amniotic fluid can cause inflammation and affect bowel function.

Understanding these features allows clinicians to distinguish gastroschisis from other abdominal wall defects, which is critical for prenatal diagnosis, surgical planning, and counseling the family.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th Edition, Chapter 17: Congenital Anomalies and Genetic Disorders, Page 945