VAN 221: Veterinary Splanchnology and Applied Anatomy (1+1)

PERITONEUM AS A WHOLE

Ox

• Tracing the peritoneum as a whole, we may consider it as consisting of two sacs a greater and a lesser
• The greater sac lines the greater part of the abdominal cavity and covers most of the viscera, which have a peritoneal investment
• The lesser sac formed by the two layers of greater omentum, is an introversion or invagination of the greater sac, formed during the development of the viscera
• The cavity of the greater sac is termed general peritoneal cavity
• The cavity of the lesser sac is the omental cavity - a potential space, similar to the general peritoneal cavity
• The two cavities communicate by a relatively narrow passage termed the epiploic foramen (foramen of Winslow). This opening is situated on the visceral face of liver
• It is almost sagittal in direction, formed between caudate lobe of liver dorsally and portal vein and pancreas ventrally
• Its walls are normally in contact and the passage merely a potential one.
• We may now trace the peritoneum in a longitudinal direction beginning in front
• It is reflected from the ventral abdominal wall and the diaphragm upon the liver forming the ligaments of the liver and its serous coat
• It leaves the liver as lesser omentum and becomes continuous with the mesoduodenum and greater omentum
• From the dorsal abdominal wall it is reflected on the rumen and spleen to form their serous coat and greater omentum on the left
• The reflection from the dorsal abdominal wall in the midline forms the common terminal part of the colon in the sublumbar region and the rectum in the pelvic cavity forming the mesocolon and mesorectum respectively
• It is then reflected from the rectum to the dorsal surface of the bladder to form the genital fold (broad ligaments in the female) and passes to the body wall laterally and ventrally to form the lateral and middle ligaments of the bladder. In the newborn, the following folds are very large
• The falciform ligament of liver extends to the umbilicus, and contains in its free edge the large umbilical vein
• The bladder at this time an abdominal organ has a ventral median fold, which connects it and the umbilicus and contains the large umbilical artery