Overview
The peritoneum is a thin membrane that separates the intra-abdominal
contents, helping to support them and also allow blood and lymph vessels to
pass.
Gross Anatomy
It consists
of 2 layers, the parietal and visceral peritoneum. The parietal peritoneum
lines the internal surface of the abdominal cavity and the visceral peritoneum
lines the intra-abdominal viscera; however it is a continuation of the parietal
peritoneum. Some organs are classed as retroperitoneal structures, that is to
say that they have only an anterior surface covering of peritoneum. Examples of
these include the kidneys and aorta.
The
peritoneum forms double layered folds called mesentery. It most commonly
relates to the small bowel from which it is the source of its lymph and blood
supply but is also found on other organs such as the appendix and sigmoid
colon, for example.
The
peritoneum forms the omentum, a 4 layer fold of peritoneum. The greater omentum
extends for the greater curvature of the stomach and proximal duodenum, then
folds back on itself to insert onto the transverse colon.
It also forms
the lesser omentum, which extends from the liver to the lesser curvature of the
stomach and first part of the duodenum. It has a free border which contains the
common bile duct, hepatic artery and portal vein.
Behind the
lesser omentum is the lesser sac. On the left it is bounded by the
gastrosplenic and lienorenal ligaments. On the right it communicates with the
greater sac via the epiploic foramen. Its boundaries are outlined below.
Boundaries
of the epiploic foramen
Anterior |
The free border of the lesser omentum |
Posterior |
Inferior vena cava |
Inferior |
D1 |
Superior |
Caudate process of the liver |
Clinical Anatomy
Pain
in appendicitis
The nerve supply of the parietal and visceral peritoneum
also differs slightly. The parietal peritoneum is innervated by somatic fibres
that also supply the abdominal wall, however the visceral peritoneum is
dependent on its corresponding viscera so is poorly localised. Hence why in
appendicitis the pain classically localises later in the disease to the right
iliac fossa due to late parietal irritation as compared to early poorly
localised visceral peritoneal inflammation.
Pringle’s
manoeuvre
During liver surgery if there is damage to the
hepatic artery or portal vein it can be controlled via compression at the free
border of the lesser omentum. This is known as Pringle’s manoeuvre.
Quick Anatomy
Key Facts
Aide-Memoire
Retroperitoneal organs:
SADPUCKER- Suprarenal glands, Aorta,
Duodenum, Pancreas (not the tail), Ureters,
Colon (ascending and descending) Kidneys, Oesophagus, Rectum
Summary
References
Gosling
et al. Human Anatomy. Fourth Edition.
Mosby Publishing 2002
Dean
& Pegington. Core Anatomy for Students. Volume 2: The Thorax, Abdomen,
Pelvis & Perineum. Saunders. Elsevier Science. 2002
S
Jacob. Atlas of Human Anatomy Second Edition. Elsevier 2005