Step 1 - Dissection of the Abdominal Mesenteries and Celiac Trunk
Once you have opened the abdominal cavity, it is your only opportunity to appreciate the "in situ"
relationships of the mesenteries and organs. Take time to explore the entire cavity and peritoneal
relections. Begin by palpating the liver, gall bladder, stomach, the lesser omentum and greater omentum
as seen in this dissection. NOTE: Remember, the peritoneum is a continuous layer, which means that you can move your
finger throughout the entire cavity and return to the place you started without lifting your finger.
Find the pylorus and follow the duodenum until it become retroperitoneal at its second part. Pick
up the duodenal-jejunal junction and follow the entire length of the small intestine (jejunum and
ileum) to the ileocecal junction. Trace the cecum (with appendix), ascending colon,
transverse colon, descending colon and
sigmoid colon to the rectum.
Along the way, find
the lesser omentum, transverse mesocolon, and
the mesentery.
Appreciate how the lesser sac is formed and how it communicates with the greater
sac through the epiploic foramen
(of Winslow). NOTE: The epiploic foramen provides access to the posterior wall of the stomach and other
viscera in this region without cutting the peritoneum.
This is the only opportunity you will have to feel other named ligaments, which were described in
lecture, because they will soon be destroyed. Ask your instructor if you have trouble finding them.
Before you begin to remove the mesenteries, palpate the spleen, pancreas and kidneys.
