ANATOMY OF THE INTRAPERITONEUM

Thorsang Chayovan, MD

R1, Radiology

Prince of Songklanagarind University

GI TOPIC 30 April 2014

Outline

• The peritoneum and the peritoneal spaces

• The intraperitoneal organs

• The vascular supply

The peritoneum and the peritoneal spaces

• The peritoneum

– Parietal peritoneum

abdominal wall

– Visceral peritoneum

organs

• The peritoneal cavity – Greater

• Supramesocolic

• Inframesocolic

– Lesser

• The peritoneal ligaments, mesentery, and omentum

The peritoneal cavity

• potential space between the parietal and visceral peritoneum and contains a film of fluid that lubricates the surface of the peritoneum and facilitates free movements of the viscera.

• Is a completely closed sac in the male but is open in the female through the uterine tubes, uterus, and vagina. It is divided into the lesser and greater sacs.

Definitions

• Ligament

– Two folds of peritoneum

– Supporting structures

• Mesentery

– Two folds of peritoneum

– Connecting to the posterior abdominal wall

• Omentum

– Connecting the stomach to other organs

• The greater omentum

– connects the stomach

to the colon

• The lesser omentum

– connects the stomach

to the liver

Omentums

Greater omentums

• Gastrocolic ligament

• Gastrosplenic ligament

• Gastrophrenic ligament

• Gastrolienal (Gastrosplenic) Ligament – จากด้านซ้ายของ greater curvature – ขัว้ม้าม contains

the short gastric and left gastroepiploic vessels.

• Lienorenal (Splenorenal) Ligament – จากขัว้ม้ามไปไตซ้าย contains the splenic vessels and

the tail of the pancreas.

• Gastrophrenic Ligament – จากสว่นบนของ greater curvature ไป diaphragm.

• Gastrocolic Ligament – จาก greater curvature ไป transverse colon.

Lesser omentums

• Gastrohepatic ligament

• Hepatoduodenal ligament

• Gastrohepatic ligament:

– connects the left lobe of the liver to the lesser curvature of the stomach

• Hepatoduodenal ligament:

– free edge of the omentum, which contains the portal vein, hepatic artery and common bile duct

– CBD, hepatic gasteic vv, portal vein

lesser omentum

• coronary veins (ท่ี dilate เป็น varices ได้)

• lymph nodes (ท่ีโตได้จาก gastric carcinoma and

lymphoma)

• part of anterior wall of lesser sac

Lesser sac

• lesser sac เป็นสว่นหนึง่ในช่องท้อง ท่ีอยูร่ะหวา่ง stomach

and the pancreas

• ตอ่กบัภายนอกคือ greater sac ผา่นทาง foramen of Winslow (epiploic foramen)

• aorta + celiac a อยู ่posteror to lesser sac

• ความผิดปกติใน lesser sac จะเกิดจาก organ ข้างเคียง (pancreas, stomach) มากกวา่จากท่ีอ่ืน ปกติจะ collapsed ยกเว้นท่ี fluid fill

Lesser sac

• (a) superior recess, which lies behind the stomach, lesser omentum, and left lobe of the liver;

• (b) inferior recess, which lies behind the stomach, extending into the layers of the greater omentum

• (c) splenic recess, which extends to the left at the hilus of the spleen.

Mesenteries

• Double folds of the peritoneum

• connect to the posterior abdominal wall

– The small bowel mesentery

– The transverse mesocolon

– The sigmoid mesentery (or mesosigmoid)

Root ของ transverse mesocolon แบง่ peritoneal cavity เป็น supramesocolic and inframesocolic space ที่ตอ่ถงึกนัทาง paracolic gutter

Paracolic gutter 2 ข้าง form ขึน้ด้วย asc + des colon + lat abd wall จะเหน็ได้วส่ามารถเกิด peritoneal recess ขึน้ได้มากมายระหว่าง bowel loops และ mesentery ของมนั

The peritoneal spaces

Right Left

Right peritoneal spaces

• Right subphrenic space

• Right subhepatic space: anterior and posterior

• Bare area

- Right ant. Subhep. Space Connecting to epiploic foramen

- posterior subhepatic space (Morison pouch) – dependent part

• Right subphrenic space

• Right subhepatic space:

– Anterior right subhepatic space

– Posterior right subhepatic space

• Hepatorenal fossa (Morrison pouch)

• Bare area

• Immediate left subphrenic space

• Left subhepatic space

• Falciform ligament

Left peritoneal spaces

Left subhepatic space • gastrohepatic recess

• affected by diseases of the duodenal bulb, lesser curve of the stomach, gallbladder, and left lobe of the liver.

Peritoneal circulation

• Predominantly to right paracolic gutter – deeper and wider than

the left – partially cleared by the

subphrenic lymphatics.

• Watershed regions - fluid stasis: – Ileocolic region – Root of the sigmoid

mesentery

• Malignancy staging

GASTROINTESTINAL TRACT

Stomach

Small intestine

Duodenum 1st part อยู่ intraperitoneum 2nd part มดุลง retro; ติดกบั pancreatic head อย่ใกล้ขัว้ไตขวา; มี Root of trannsverse mesocolon + mesentery cross ทบั 3rd part cross หน้า aorta + IVC หลงั SMA + SMV Jejunum กลบัมาอยู่ intraperitoneum

Jejunum

Ileum

Large intestine

Cecum

Posterior peritoneal attachment

LIVER

Note

• Falciform Ligament

– Is a sickle-shaped peritoneal fold connecting the liver to the diaphragm and the anterior abdominal wall.

– Contains the ligamentum teres hepatis and the paraumbilical vein, which connects the left branch of the portal vein with the subcutaneous veins in the region of the umbilicus.

• Ligamentum Teres Hepatis (Round Ligament of the Liver)

– Lies in the free margin of the falciform ligament and ascends from the umbilicus to the inferior (visceral) surface of the liver, lying in the fissure that forms the left boundary of the quadrate lobe of the liver.

– Is formed after birth from the remnant of the left umbilical vein, which carries oxygenated blood from the placenta to the left branch of the portal vein in the fetus. (The right umbilical vein is obliterated during the embryonic period.)

Note

• Coronary Ligament

– Is a peritoneal reflection from the diaphragmatic surface of the liver onto the diaphragm and encloses a triangular area of the right lobe, the bare area of the liver.

– Has right and left extensions that form the right and left triangular ligaments.

• Ligamentum Venosum

– Is the fibrous remnant of the ductus venosus.

– Lies in the fissure on the inferior surface of the liver, forming the left boundary of the caudate lobe of the liver.

PV HA BD ไปด้วยกนัตลอด -> เรียก Portal triad แตล่ะ segment จะถกูเลีย้งด้วยแขนงเหลา่นี ้HV จะอยู่ระหว่าง hepatic segment แต ่PT เข้าไปใน segment

ตบัด้านหลงัเหน็ caudate อยู่ entirely posterior ติดกบั IVC, ligamentum venosum, porta hepatis Plane ที่ผ่าน IVC + gallbladder แบง่ Lt/Rt lobe

• Each segment has its own vascular inflow, outflow and biliary drainage.

• ด้านในเลีย้งด้วย PT ด้านนอก ด้วย hepatic veins.

• Right hepatic vein divides the right lobe into anterior and posterior segments. Middle hepatic vein divides the liver into right and left lobes (or right and left hemiliver). This plane runs from the inferior vena cava to the gallbladder fossa. Left hepatic vein divides the left lobe into a medial and lateral part.

• Portal vein divides the liver into upper and lower segments. The left and right portal veins branch superiorly and inferiorly to project into the center of each segment.

• Because of this division into self-contained units, each segment can be resected without damaging those remaining. For the liver to remain viable, resections must proceed along the vessels that define the peripheries of these segments. This means, that resection-lines parallel the hepatic veins, The centrally located portal veins, bile ducts, and hepatic arteries are preserved

GALLBLADDER

Variation 20% Most accessory duct on the right side เข้า common hepatic duct (/cystic/CBD)

Accessory Lt duct enter CBD

PANCREAS

SPLEEN

Spleen วางบน diaph level rib 9-10 ติด stomach ด้วย gastrosplenic (short gastric, gastroomental a) ติดไตซ้ายด้วย splenorenal (splenic vv)

VASCULATURE

Celiac trunk

SMA

References

• Gray, Henry, Richard L. Drake, Wayne Vogl, Adam W. M. Mitchell, Richard Tibbitts, and Paul Richardson. Gray's Anatomy for Students. Philadelphia: Elsevier/Churchill Livingstone, 2010.

• "Imaging Anatomy: Chest, Abdomen, Pelvis | Amirsys Publishing." Amirsys Publishing. N.p., n.d.

• Knipe, Henry, MD, and Jeremy Jones, MD. "Peritoneum." Radiopaedia Blog RSS. N.p., n.d. Web. 21 Apr. 2014.

• Devy, Angela D., MD. "Peritoneum and Mesentery - Part I: Anatomy." The Radiology Assistant :. N.p., n.d. Web. 21 Apr. 2014.

• Smithuis, Robin, MD. "Anatomy of the Liver Segments." The Radiology Assistant :. N.p., n.d. Web. 26 Apr. 2014.

THANK YOU