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Abdomen 3
2.6 Jejenum, ileum and colon
Albert van Schoor
GNK 288 (SA4 Anatomy dissection)
2.6 Jejenum, ileum and colon
2.6.1 Surface anatomy
2.6.2 Structure
2.6.3 Blood supply and lymph drainage
2.6.4 Embryology
2.6.5 Radiographic anatomy
2.6.1 Surface anatomy
• Identify and describe in which region the
jejunum and ileum are found
• Review in which region the ascending,
transverse and descending colon,
caecum, appendix and sigmoid colon
are found
2.6.1 Surface anatomy
Jejenum & ileum
2.6.1 Surface anatomy
Colon
2.6.2 Structure
• Identify and name the origin and
termination of the jejunum and ileum
• Identify the general and peritoneal
relations of the jejunum and ileum
• Compare and identify the blood supply,
mucosal pattern, mesenterium and
cross section of the proximal jejunum
and distal ileum
2.6.2 Structure
Proximal Jejenum
Distal ileum
2.6.2 Structure
• Compare and identify the differences
between the small intestine and colon
• Name and identify the duodenojejunal
and ileocolic junctions and the root of
the mesentery running between these
points
2.6.2 Structure
Differences
Large & small intestines
• Teniae coli
• Haustra
• Omental appendices /
Appendices epiploica
• Semicircular folds
• Large diameter
• No teniae coli
• No Haustra
• No Omental appendices
/ Appendices epiploica
• Circular folds
• Small diameter
2.6.2 Structure
• Identify and briefly discuss the division
of the large intestine into the caecum,
appendix, ascending colon, transverse
colon, descending colon and sigmoid
colon, their structure and general and
peritoneal relationships
2.6.2 Structure
Cecum & appendix
2.6.2 Structure
Ascending colon
2.6.2 Structure
Transverse colon
2.6.2 Structure
Descending colon
2.6.2 Structure
Sigmoid colon
2.6.2 Structure
• Briefly discuss and identify the anatomy
of the appendix regarding its various
positions, mesentery, blood supply and
surface anatomy
2.6.2 Structure
Appendix
2.6.3 Blood supply and lymph drainage
• Schematically illustrate the arterial
blood supply of the ileum, jejunum and
colon
• Name and identify the superior and
inferior mesenteric vessels
• Name and identify the arterial
anastomoses between the foregut and
midgut and midgut and hindgut
2.6.3 Blood & Lymph
Midgut
Superior mesenteric artery
• Anterior inferior
pancreaticoduodenal
artery
• Intestinal arteries
• Vascular arcades
• Straight arteries
• Middle colic artery
• Right colic artery
• Marginal arteries
• Ileocolic artery
2.6.3 Blood & Lymph
Hindgut
Inferior mesenteric artery
• Left colic artery
• Marginal artery of
Drummond
• Sigmoid branches
• Superior rectal artery
• Rectosigmoid
2.6.3 Blood supply and lymph drainage
• Name and identify the portal venous drainage
of the jejunum, ileum and colon
• Schematically illustrate the formation, course
and relations of the hepatic portal system
• Explain the difference between the portal and
systemic (caval) venous systems
• List the vessels taking part in the 5 portocaval anastomoses
2.6.3 Blood & Lymph
• Oesophagus
– Left gastric vein (P)
– Azygos vein (S)
• Rectum
– Superior rectal vein (P)
– Middle & inferior rectal veins
& pelvic venous plexus (S)
• Umbilicus
– Para-umbilical veins (P)
– Superficial & inferior
epigastric veins (S)
• Spleen & colon
– Splenic & colic veins (P)
– Renal vein, IVC & Abdominal
wall veins (S)
• Bare area of liver
– Hepatic veins (P)
– Diaphragmatic & azygos
veins (S)
2.6.3 Blood supply and lymph drainage
• Give a broad overview of the major
lymphnode groups to which the lower
abdominal organs
2.6.4 Embryology
• Briefly discuss the embryological
divisions of the foregut, midgut and
hindgut, and state the blood supply and
nerve supply of each
2.6.4 Embryology
Shape changes of trilaminar embryo disc
Germ layers
Ectoderm
Mesoderm
Endoderm
Folding
Derivatives
Ectoderm
Communication
Mesoderm
Movement
Endoderm
Nutrition
2.6.4 Embryology
Endoderm
• Foregut
– Pharynx, palatine tonsils, thyroid gland, esophagus,
stomach, 1st & 2nd parts of duodenum, trachea and
branches, liver, gallbladder and pancreas
• Midgut
– 3rd & 4th parts of duodenum, jejunum, ileum, ascending
and 2/3 transverse parts of colon
• Hindgut
– 1/3 Transverse colon
– Descending & sigmoid parts of colon
– Cloaca gives rise to rectum, anus & part of urinary
bladder
– Allantois forms part of urinary bladder
– Cloacal membrane breaks down = gut communicates
with amniotic cavity
2.6.5 Radiographic anatomy
• Compare the differences between large
and small intestine on a plain erect
abdominal X-ray and barium-meal
www.up.ac.za/academic/medicine/anatomy/current/sa4/week01e.html#radio