The Abdomen

Stuart M Bunt

Functional Anatomy 212

Overview

Embryology Revision

Foregut, Midgut and Hindgut suspended by the dorsal mesentary, initially straight

Ventral mesentary connects stomach and ant. abd. wall, rest of gut free anteriorly

Mesentary supplies blood and nerves to gut between layers of peritoneum

Complex adult layout due to 270o rotation

Blood Supply to Abdominal Organs Foregut

Celiac trunk Midgut

Superior mesenteric artery Hindgut

Inferior mesenteric artery Rectum

Internal iliac artery (pudendal and rectal arteries)

Stomach Variable size and shape,

distensible J shaped related to body

form Lesser and greater

curvature gastroesophageal

junction fundus,cardiac part,

body, pyloric part pyloric antrum and

sphincter rugae and gastric pits

Blood Supply of Stomach

Superior Mesenteric Artery Territory

Inferior mesenteric artery territory

Venous system

Portal Vein Splenic vein

inferior mesenteric vein

Superior mesenteric vein

Gastric veins Hepatic Veins

Inf. Vena CavaInf. Vena Cava

Anastomoses

Stomach rotates and distends

Front

Back

OmentumOmentum

Dorsal Dorsal MesentaryMesentary

VentralVentralMesentaryMesentary

Splenic Splenic tissuetissue

Epiploic Foramen

Omentum

Under the OMENTUM

The Peritoneal cavity is divided in two

Rotation of stomach forms the greater omentum(allows stomach distension and infection control)

Omental bursa or Lesser sac is inside omentum (a potential space)

Lesser omentum runs from stomach to liver(note free lower border above epiploic foramen

contains portal vein, hepatic artery and bile duct

Falciform ligament runs from liver to ant abd. wall

Mesenteries are important:-

Paracolic gutters channel fuid Stop herniation due to bipedal posture Supply blood/nerves Sensitive to stretch Contain infection Useful in surgery

On return some gut fuses with posterior wall

Rectum

Desc. ColonAsc. Colon

Duo.

12

3

41.lienorenal lig.2.trans. mesocolon3.mesentary proper4.mes. of sig. colon

Diaphragm

Retro-peritoneal

Oesophagus 10 inches from pharynx to stomach narrow

at cricoid cartilage where left bronchus crosses oesophageal hiatus in diaphragm

mucous membrane folded (normally collapsed) stratified squamous epithelium striated above smooth below trachea on right, lower aorta on left medial to L. lung, behind left atrium

Duodenum

first 12 inches of gut four parts form C shape

duodenal cap radiologically identified, ulcers form here mobile

descending part pancreatic and bile ducts

horizontal part crosses psoas, IVC and aorta crossed by mesentery, sup mesen. art.

ascending part

Jejunum 2/5ths of small

intestine gradual transition to

ileum many small villi increasing numbers of

lymph nodules no submucosal glands lacteals in each villus columnar epithelium

Ileum

distal 3/5ths of intestine narrower, thinner, less

vascular, slower, more fat and arterial arcades

in mesentery than jejunum. Peyer’s patches of lymphoid

tissue

Colon ascending colon

retroperitoneal right colic or hepatic

flexure transverse colon

(mesocolon) droops towards pelvis? left colic or splenic

flexure descending colon

retroperitoneal pelvic or sigmoid colon S

shaped

Colonoscopy

Barium enema outlines structures on X-rays

Appendix

The Liver Largest Gland (one

of largest organs) Right upper

abdomen under diaphragm

Grows as outgrowth of gut plus mesoderm

Diaphragmatic surface

Visceral surface down and left related to

stomach, duodenum, r. kidney, r. colonic flexure

bears gall bladder

Biliary System R and L Hepatic ducts Common hepatic duct Joined by cystic duct (to

gall bladder) Forms bile duct

(common bile duct) Gall Bladder

body and fundus, salts and water absorbed

store for bile, released in response to cholecystokinin

Pancreas

Pancreas

Head in concavity of duodenum body across vertebrae tail reaches the spleen pancreatic duct (+ accessory?) ampulla duodenal papilla

Spleen

The Spleen Lies in left hypochondriac region between

gastric fundus and diaphragm at level of 9th-10th rib (not normally palpable)

Soft, friable, highly vascular, dark purple Diaphragmatic surface

convex and smooth facing diaphragm Visceral surface

gastric, renal, pancreatic and colic impressions

The Spleen (2)

Hilum of spleen long fissure through which vessels and nerves pass

Suspended from stomach by gastrolienal ligament (contains short gastric and left gastro-epiploic branches of spenic artery)

Suspended from posterior abdominal wall by lienorenal ligament

Covered by adherent peritoneum

Relationship to the Spleen

Kidneys

In fat capsule

Suprarenal glands superiorly

Direct Arterial and venous supply

Kidney Internal Structure Renal pyramids

between renal columns

Renal Cortex Renal papillae

drain into minor calix

Major calix join to form renal pelvis

Ureter as outlet

Kidneys External View

Artery - Vein - Ureter

Relationships of the Kidneys