Oesophagus, Stomach And Duodenum

Front 1

Oesophagus

Back 1

25 cm long muscular tube from pharynx (C6) to stomach (T11)

Front 2

Cricopharyngeus muscle

Back 2

Called the “upper oesophageal sphincter” but is actually part of the pharynx
Lowest part of the inferior constrictor muscle
Tonically contracted, relaxes with swallowing

Front 3

Oesphagus Histology

Back 3

Mucosa
Loosely connected to muscle
Lined by stratified squamous epithelium
At Z-line, in lower oesophagus, there is a sudden change of mucosa to columnar epithelium (type found in stomach).
Squamo-columnar junction (Z-line) Normally close to diaphragmatic inlet
~40 cm from incisors
Pink to red colour change

Front 4

Oesphagus Transitions

Back 4

Front 5

Oesophagus - relationships

Back 5

Anterior relationships: trachea to T4, left main bronchus, pericardium & heart
Posterior relationships: vertebrae in upper 2/3rds, then aorta passes behind oesophagus.

Front 6

Significance of constriction points

Back 6

foreign bodies tend to lodge; common sites of carcinoma, scarring & strictures after swallowing

Front 7

Oesophagus - relationships & constrictions

Back 7

Front 8

Stomach

Back 8

Stomach is expanded part of digestive tract between oesophagus and duodenum
Function: food reservoir & food blender; storage (1.5-3L); chemical & mechanical breakdown of food; chyme (semi-liquid mixture) passes through pyloric orifice to duodenum.
In supine position stomach commonly lies in left hypochondrium, epigastrium, umbilical and left flank (see lower middle image)

Front 9

Stomach – external features

Back 9

4 parts of stomach: cardia, fundus, body, pyloric part
2 surfaces (anterior, posterior),
2 curvatures (greater, lesser),
2 notches (cardiac, angular),
2 openings (cardiac, pyloric orifice)

Front 10

Stomach – internal features

Back 10

Mucous membrane of empty stomach is thrown into folds called rugae. Rugae flatten as stomach distends.
Muscular wall – 3 layers (rest of GIT has only 2 layers, inner circular & outer longitudinal)
Circular layer thickens to form the pyloric sphincter Pyloric stenosis (stenosis due to thickened pyloric sphincter)  projectile vomiting

Front 11

Stomach & peritoneal relationships

Back 11

Stomach is intraperitoneal - anterior and posterior surfaces are covered by peritoneum At the greater and lesser curvatures, peritoneum forms the greater and lesser omentum

Front 12

Lesser omentum

Back 12

Lesser omentum passes to liver and has two parts: hepatogastric ligament and hepatoduodenal ligament (contains the portal triad)

Front 13

Greater omentum

Back 13

Greater omentum is the gastrophrenic, gastrolienal and gastrocolic ligaments collectively

Gastrocolic part is most often simply called the greater omentum It folds back on itself to form an apron-like structure (4 layers of peritoneum) “Policeman of abdomen” – adheres to & seals off sites of inflammation in peritoneal cavity

Front 14

Stomach Relationships

Back 14

Anterior: liver, diaphragm, anterior abdominal wall
Posterior (“stomach bed”): through the lesser sac it is related to: diaphragm, left suprarenal gland, left kidney, pancreas, splenic artery, transverse colon & transverse mesocolon; and through the greater sac it is related to the spleen.

Front 15

Duodenum (Latin = twelve)

Back 15

(12 fingerbreadths long = 25cm long)
Duodenum is first part of small intestine, and is the shortest (25cm), widest and most fixed part of small intestine. L1-L3 vertebral levels
Function: digestion & absorption; 2nd part of duodenum receives secretions from liver and pancreas (via bile & pancreatic ducts).
Relationship to peritoneum: retroperitoneal, except first few cms of superior part, which has omenta attached
Root of transverse mesocolon crosses 2nd part, root of the mesentery crosses 3rd & 4th part

Front 16

Duodenum – internal features

Back 16

Circular folds in all but first few cms of duodenum, which is called the duodenal cap on radiographs
Bile duct and main pancreatic duct open at major duodenal papilla
Accessory pancreatic duct opens at minor duodenal papilla (approx 2 cm above)

Front 17

Arterial supply – stomach & duodenum

Back 17

Remember: Stomach derived from foregut; duodenum is derived from foregut and midgut
Stomach is supplied by all 3 branches of the coeliac trunk. Lesser curvature by left & right gastric arteries, greater curvature by left & right gastroepiploic (gastro-omental) and fundus by short gastric arteries
Duodenum is supplied by branches of coeliac trunk and SMA - the superior and inferior pancreaticoduodenal arteries respectively (each have anterior and posterior branches)

Front 18

Back 18

1. R. gastric a.
2. Gastroduodenal a.
3. R. gastric a.
4. R. gastroomental (gastroepiploic) a
5. Superior pancreaticoduodenal a.
6. L. gastroomental (gastroepiploic) a
7. Splenic a.
8. Short gastric as. (4-5).
9. L. Gastric a.
10. Coeliac trunk
11. Common hepatic a.
12. Proper hepatic a

Front 19

Neurovascular supply – stomach & duodenum

Back 19

Front 20

Neurovascular supply – oesophagus

Back 20

Front 21

Barium Meal

Back 21

Front 22

Achalasia

Back 22

(lower oesophageal sphincter fails to relax normally with swallowing)