Laparoscopic abdominal anatomy of foals positioned in dorsal recumbency

Eleven foals (nine cadavers and two anesthetized) positioned in dorsal recumbency were examined to describe normal abdominal anatomy viewed by laparoscopy. The foals ages ranged from 1 to 150 days. Insertion sites were selected for a Verres needle, laparoscope and instrument portals to avoid trauma to the umbilical structures. The abdominal cavity was insufflated to a pressure of 10 to 12 mm Hg using an automatic carbon dioxide insufflator. Laparoscopic examination allowed excellent observation of the umbilical structures, the bladder, the genital tract, the inguinal area, the liver and segments of the intestinal tract in all foals. However, the duodenum and ileum were not identified. An embryonic vestige of the yolk stalk (ductus pedunculi vitellini) was identified in six foals. In four foals, this appeared as a fibrous band extending from the umbilicus to the cranial abdominal cavity where it inserted on the small intestine. In two foals only the fibrous umbilical portion of the band was observed.