Class 1

Question 1

Which structures enclose the posterior abdomen?

Answer 1

Lumbar vertebrae, intervertebral discs and inferior ribs.

Question 2

What are the 9 regions of the abdomen?

Answer 2

Right hypochondriac Epigastric Left hypochondriac
Right flank Umbilical Left flank
Right iliac Hypogastric Left iliac

Question 3

What are the 2 imaginary horizontal lines above and below the umbilicus?

Answer 3

Above - transpyloric

Below - transtubercular

Question 4

Name the 3 flat muscles and 2 vertical muscles of the anterolateral abdominal wall.

Answer 4

3 flat muscles: external oblique, internal oblique, transversus abdominis.

2 vertical muscles: rectus abdominis, pyramidalis.

Question 5

What are the actions and innervation of the external oblique?

Answer 5

Actions: compression of the abdominal cavity and lateral flexion.

Innervation: T7-T11 (lower 5 thoracoabdominal nerves) and T12 (R and L subcostal nerves).

Question 6

What are the actions and innervation of the internal oblique?

Answer 6

Actions: compression of the abdominal cavity; unilateral contraction rotates the trunk vertically to 1 side.

Innervation: ventral rami of T7-T12 and L1.

Question 7

What are the actions and innervation of the transversus abdominis?

Answer 7

Actions: aids forced respiration, supports the abdominal wall and raises intra-abdominal pressure.

Innervation: ventral rami of T7-T12 and L1.

Question 8

What are the actions and innervation of the rectus abdominis?

Answer 8

Actions: flexion of the lumbar spine and forced expiration.

Innervation: ventral rami of T7-T12 and L1.

Question 9

What is the rectus sheath?

Answer 9

This is formed by the aponeuroses of the 3 flat muscles (external oblique, internal oblique and transversus abdominis) and encloses the rectus abdominis and pyramidalis muscles.

Question 10

How does the rectus sheath differ above and below the umbilicus?

Answer 10

Above: external oblique passes in front of the rectus as does half of the internal oblique (anterior wall of the sheath). Other half of internal oblique passes behind, as does the transversus abdominis (posterior wall of the sheath).

Below: all 3 muscles pass in front of the rectus –> all are now anterior (no posterior wall) and in contact with transversalis fascia.

Question 11

Where is the umbilicus located on the abdominal wall?

Answer 11

L3/L4. Surface marking of aortic bifurcation.

Question 12

Which dermatome is at the level of the umbilicus?

Answer 12

T10

Question 13

What is the inguinal canal?

Answer 13

It is formed from layers of the anterior abdominal wall as these layers push through the wall during relocation of the gonads in fetal development. In males this canal carries the spermatic cords, in females the round ligament of the uterus. In both it carries the ilioinguinal nerve.

Question 14

Where is the inguinal canal located?

Answer 14

Parallel to and above the medial half of the inguinal ligament. The canal is approx 4cm long.

Question 15

What are the bony attachments of the inguinal ligament?

Answer 15

Pubic tubercle and anterior superior iliac spine.

Question 16

Define cryptorchidism.

Answer 16

Failure of the testes to descend from the abdomen. Most common birth defect of male genitals.

Question 17

What are the boundaries of the inguinal canal?

Answer 17

Anterior wall: aponeurosis of external oblique.

Posterior wall: transversalis fascia.

Roof: internal oblique and transversus abdominis.

Floor: inguinal ligament.

Question 18

Where are the inguinal rings located?

Answer 18

Deep inguinal ring is located superiorly and is the entrance to the inguinal canal. Superficial inguinal ring is located inferiorly and lies 1cm above and superolateral to the pubic tubercle.

Question 19

Which type of hernia is the most common?

Answer 19

Indirect inguinal hernia.

Question 20

What is the difference between a direct and indirect inguinal hernia?

Answer 20

Direct: 1/3 of inguinal hernias. Abdominal contents pass through a weak spot in the muscles making up the posterior inguinal canal. Contents enter canal and may pass through the superficial inguinal ring. Abdominal contents don’t pass through the deep inguinal ring.

Indirect: 2/3 of inguinal hernias. Due to a congenital weakness of the deep inguinal ring which allows abdominal contents to enter into the inguinal canal and out through the deep inguinal ring.

Question 21

What is a femoral hernia?

Answer 21

A hernia that occurs below the inguinal ligament. Abdominal contents pass into a weak area of the posterior wall of the femoral canal. More common in females and risk of strangulation.

Question 22

What is a strangulated hernia?

Answer 22

A hernia in which the blood supply has been cut off to the protruding tissue.

Question 23

What is an umbilical hernia?

Answer 23

Abdominal contents pass through a weakness in the abdominal wall at the site of the umbilicus. In adults umbilical hernias are acquired, not congenital.

Question 24

What are the 4 histological functional layers of the gut tube?

Answer 24

1) Mucosa - a) epithelium, b) lamina propria, c) muscularis mucosae
2) Submucosa
3) Muscularis externa - outer longitudinal layer and inner circular layer
4) Serosa (intraperitoneal) or adventitia (retroperitoneal)

Question 25

What are the 4 basic mucosal forms of the GI tract?

Answer 25

Protective: oral cavity, pharynx, oesophagus and anal canal.

Secretory: stomach.

Absorptive: small intestine.

Absorptive/protective: large intestine.