2 - Anatomy of the Gut

Question 1

What are the muscles that make up the anterior abdominal wall?

Answer 1

Question 2

What is the rectus sheath?

Answer 2

Where the aponeuroses from the three lateral abdonimal muscles surrounded the central rectus abdominus muscle

Question 3

What way do the fibres of the lateral abdominal muscles run?

Answer 3

• External obliques hands in pocket, internal perpendicular to this
• Transversus runs horizontal

Question 4

How does the rectus sheath vary as you go down the abdomen?

Answer 4

• Below the arcuate line the aponeurosis is only lying on the anterior so rectus muscle directly on transversalis fascia
• Arcuate line halfway between umbilicus and pubis

Question 5

What is the peritoneal cavity?

Answer 5

• Mesothelium simple squamous lined cavity containing lubricating fluid

- Parietal peritoneum touches the abdominal wall whereas visceral is in contact with the organs

• In males the cavity is enclosed but in females it opens at the entrance of the fallopian tubes

Question 6

What are some retroperitoneal organs?

Answer 6

• Retroperitoneal organs only have their anterior aspect covered by parietal peritoneum, e.g kidneys, and suprarenal glands
• Duodenum, ascending colon, descending colon, middle third of the rectum, and pancreas

Question 7

What is a mesentry?

Answer 7

• Double layer of visceral peritoneum that has fat, lymph vessels and blood vessels between it. Allows organs to have nutrition
• Connects intraperitoneal organ to posterior abdominal wall and provides pathway for nerves, blood and lymph

Question 8

What is the innervation of the anterolateral abdominal muscles?

Answer 8

- RA: anterior rami of lower 7 thoracoabdominal spinal nerves T7-T12

- EO: anterior rami of lower 6 thoracoabdominal nerves T7 to T12

- IO: same as above plus L1

• TA: same as above

Question 9

What are the nine descriptive regions of the abdomen and what is their contents?

Answer 9

Question 10

What are the functions of the anterolateral abdominal muscles?

Answer 10

- External Oblique: compress ab contents, flex/bend and turn trunk

- Internal Oblique: same as above

- Transverse abdominis: compress ab contents

- Rectus abdominis: compress ab contents, flex vertebral column and tense ab wall

Question 11

What are the different mesentries associated with the intestines?

Answer 11

• Small bowel (J and I not D)
• Transverse mesocolon
• Sigmoid mesocolon

Question 12

What is the greater and lesser omentum?

Answer 12

Lesser: Double layer of peritoneum from liver to lesser curvature of the stomach and the duodenum

Greater: Large apron-like fold of visceral peritoneum that hangs down from the stomach.

Question 13

What is the falciform ligament?

Answer 13

Attaches the liver to the front body wall, and separates the liver into the left lobe and right lobes.

Question 14

What is the gastrocolic and gastrosplenic ligament?

Answer 14

Gastrosplenic: part of the greater omentum and connects the greater curvature of the stomach to the hilum of the spleen

Gastrocolic: greater omentum from the greater curvature of the stomach to the transverse colon. It forms part of the anterior wall of the lesser sac.

Dividing this gives access to anterior pancreas and the posterior wall of the stomach.

Question 15

What is the difference in pain between the parietal and visceral peritoneum?

Answer 15

Visceral cannot pinpoint where pain is coming from so will have referred pain. They feel pain differently as they have different embryological origins

Question 16

What is this abdominal x-ray showing?

Answer 16

Sigmoid colon torsion on sigmoid mesocolon