Gastro Practical 2.2.5

Question 1

what muscles form the rectus sheath?

Answer 1

external oblique, internal oblique, transversus abdominis

Question 2

what is the direction of the muscles fibres of the external oblique?

Answer 2

downward and forward

Question 3

what is the direction of the muscles fibres of the internal oblique

Answer 3

upward and forward

Question 4

what is the direction of the muscles fibres of the transversus abdominis

Answer 4

transverse

Question 5

what is the direction of the muscles fibres of the rectus abdominis

Answer 5

vertical

Question 6

what are the origins and insertions of the external oblique?

Answer 6

o = lower 8 ribs
i = linea alba via rectus sheath, iliac crest, lower border forms inguinal ligament

Question 7

what is the origin and insertion of the muscles fibres of the internal oblique

Answer 7

o = thoracocolumbar fascia iliac crest lateral two thirds of inguinal ligament
i = costal margin, linea alba (via rectus sheath), pubic crest and pectineal line (via conjoint tendon)

Question 8

what is the origin and insertion of the muscles fibres of the transversus abdominus

Answer 8

o= costal mergin, thoracolumbar fascia, iliac crest, lateral one third of inguinal ligament
i= linea alba via rectus sheath pubic crest and pectineal line via conjoint tendon

Question 9

what is the origin and insertion of the muscles fibres of the rectus abdominus

Answer 9

o= pubic crest
i= costal cartilages 5,6,7

Question 10

The neurovascular plane lies between which two muscle layers?

Answer 10

The neurovascular bundle lies between the middle and inner layers of the body wall (internal
oblique and transversus abdominis in abdomen; internal and innermost intercostal in thorax)

Question 11

What are the nerve supplies and actions of the abdominal muscles?

Answer 11

Nerve supply – lower 6 thoracic spinal nerves (T7-T12) + iliohypogastric & ilioinguinal (L1) for
the fibres of the conjoint tendon (‘inguinal shutter mechanism’)
Actions – move trunk (flexion, lateral rotation), compress abdomen (expiration, evacuation),
support of viscera, control of inguinal shutter mechanism

Question 12

What is the arrangement of the aponeuroses of the anterolateral abdominal wall
muscle at the following levels?
a) above the costal margin
b) between the costal margin and the arcuate line
c) below the arcuate line

Answer 12

a) Anterior sheath only (from EO aponeurosis)
b) Anterior and posterior sheath (note the splitting of the IO aponeurosis)
c) Anterior sheath only (from all 3 aponeuroses)

Question 13

What does the rectus sheath contain?

Answer 13

Rectus abdominis (+/- pyramidalis)
Superior and inferior epigastric vessels
Lower 6 intercostal nerves (T7-T12) and accompanying vessels

Question 14

In a midline incision (e.g. laparotomy) what layers would be traversed before entering
the abdominal cavity?

Answer 14

Skin
Superficial fascia (fatty layer of Camper; membranous layer of Scarpa)
Linea alba
Transversalis fascia
Extraperitoneal fat
Parietal peritoneum

Question 15

what does the inguinal canal contain?

Answer 15

in females it contains the round ligament of the uterus, the ilioinguinal nerve, and the obliterated remains of the processus vaginalis which forms the sac of an indirect inguinal hernia

in males it contains the spermatic cord the ilioinguinal nerve and the obliterated remains of the processus vaginalis which forms the sac of an indirect inguinal hernia

Question 16

• What structures form the anterior wall of the inguinal canal?

Answer 16

Anterior wall
Superficial ring (medially; weak), EO aponeurosis and IO muscle (laterally; strong)

Question 17

• What structures form the posterior wall of the inguinal canal?

Answer 17

Posterior wall
Conjoint tendon (medially, strong); transversalis fascia and deep ring (laterally; weak)

Question 18

What structures form the roof of the inguinal canal?

Answer 18

Roof
Lowermost fibres of IO and TA muscles (insert via conjoint tendon; form ‘inguinal shutter’)

Question 19

What structures form the floor of the inguinal canal?

Answer 19

Floor
Inguinal and lacunar ligaments

Question 20

From where are the coverings of the spermatic cord derived?

Answer 20

External spermatic fascia – from EO aponeurosis
Cremasteric fascia – from IO and TA muscles
Internal spermatic fascia – from transversalis fascia

Question 21

What are the contents of the spermatic cord?

Answer 21

10 structures in total:
3 arteries: testicular, cremasteric, artery of vas
3 nerves: ilioinguinal, genital branch of genitofemoral, sympathetic fibres
3 others: corresponding veins (incl. pampiniform plexus), lymphatics, vas deferens
…and the most easily forgotten:
Obliterated remains of processus vaginalis (this forms the sac of an indirect inguinal hernia)

Question 22

What are the contents of the spermatic cord?

Answer 22

10 structures in total:
3 arteries: testicular, cremasteric, artery of vas
3 nerves: ilioinguinal, genital branch of genitofemoral, sympathetic fibres
3 others: corresponding veins (incl. pampiniform plexus), lymphatics, vas deferens
…and the most easily forgotten:
Obliterated remains of processus vaginalis (this forms the sac of an indirect inguinal hernia)

Question 23

where are the attachment points of the inguinal ligament?

Answer 23

ASIS to pubic tubercle

Question 24

What structures are located at the mid-point of inguinal ligament?

Answer 24

deep ring

Question 25

What structures are located at the mid-inguinal point?

Answer 25

femoral artery

Question 26

what is the mid-point of the inguinal ligament?

Answer 26

- midway between ASIS and pubic tubercle - indicates position of deep ring

Question 27

what is the mid-inguinal point?

Answer 27

midway between ASIS and pubic symphysis - indicates position of femoral artery

Question 28

Indirect inguinal vs direct inguinal

Answer 28

- distinguished based on relationship to inferior epigastric vessels - indirect passes lateral to vessels - direct passes medial to vessels

Question 29

Indirect inguinal vs femoral

Answer 29

- distinguished based on relationship to pubic tubercle - inguinal emerges above and medial to tubercle - femoral emerges below and lateral to tubercle

Question 30

What are the boundaries of the inguinal triangle of Hesselbach and why is it useful to define?

Answer 30

Boundaries: inguinal ligament, inf. epigastric vessels, edge of rectus sheath (linea semilunaris) Significance: a direct inguinal hernia pushes forward through the triangle (medial to the IEA)

Question 31

What are the boundaries of the inguinal triangle of Hesselbach and why is it useful to define?

Answer 31

Boundaries: inguinal ligament, inf. epigastric vessels, edge of rectus sheath (linea semilunaris) Significance: a direct inguinal hernia pushes forward through the triangle (medial to the IEA

Question 32

What are the boundaries of the inguinal triangle of Hesselbach and why is it useful to define?

Answer 32

Boundaries: inguinal ligament, inf. epigastric vessels, edge of rectus sheath (linea semilunaris) Significance: a direct inguinal hernia pushes forward through the triangle (medial to the IEA)wha

Question 33

what are the retroperitoneal organs ?

Answer 33

SAD PUCKER suprarenal aorta + ivc duodenum 2-4 pancreas (not tail) ureters colon (ascending and descending) kidneys esophagus rectum

Question 34

what organs lie intraperitoneally?

Answer 34

SALTD SPRSS S: stomach A: appendix L: liver T: transverse colon D: duodenum (first part) S: small intestines (jejunum and ileum) P: pancreas (only tail) R: rectum (upper third) S: spleen S: sigmoid colon

Question 35

describe the course of the peritoneum

Answer 35

1. The greater sac covers: * The back of the anterior abdominal wall, and passes superior to cover the inferior surface of diaphragm. * Then it reflects on the superior, anterior and inferior surfaces of liver 2. A peritoneal fold reflects from liver to stomach known as lesser omentum, which encloses stomach & then comes together to form greater omentum. 3. Greater omentum: Reflects back to enclose transverse colon & becomes transverse mesocolon. 4. Transverse mesocolon: ascends reaching pancreas & then divides into: Upper layer: continues on posterior abdominal wall. Lower layer: descends to cover posterior abdominal wall. 5. A reflection of peritoneum from the posterior abdominal wall reflects to cover jejunum and ileum known as mesentery of small intestine. 6. The peritoneum covers the posterior abdominal wall, then followed downward & continues to pelvis to form pelvic peritoneum.

Question 36

what forms the anterior wall of the lesser sac?

Answer 36

liver (caudate lobe) lesser omentum stomach greater omentum (anterior 2 layers)

Question 37

what forms the posterior wall of the lesser sac?

Answer 37

peritoneal covers structures that form the stomach bed transverse mesocolon transverse colon greater omentum

Question 38

what are the boundaries of the epiploic foramen?

Answer 38

superiorly: liver cuadate lobe inferiorly : duodenum 1st part posteriorly : ivc anteriorly : structures which are in the free margin of the lesser omentum (portal triad - hepatic artery, portal vein, and common bile duct)

Question 39

what is the lesser omentum?

Answer 39

fold of peritoneum that extends from the liver to the lesser curvature of the stomach and 1st inch of duodenum

Question 40

what is the greater omentum?

Answer 40

peritoneal fold that extends from the greater curvature of the stomach to the transverse colon folded up on itself

Question 41

what is the falciform ligament?

Answer 41

fold of peritoneum connecting the anterior abdominal wall to the liver

Question 42

what is the splenorenal ligament?

Answer 42

peritoneal fold connectinf the left side of kidney to the spleen

Question 43

what is the mesentery

Answer 43

fan shaped peritoneal fold of two layers enclosing the free part of the small intestine

Question 44

what is the sigmoid mesocolon

Answer 44

peritoneal fold enclosing the sigmoid colon

Question 45

what is the gastrosplenic ligament

Answer 45

peritoneal fold connevring spleen to stomach

Question 46

what is the transverse mesocolon

Answer 46

peritoneal fold enclosing transverse colon

Question 47

what is the mesoappendix

Answer 47

triangular peritoneal fold enclosing the vermiform appendix

Question 48

what are the names of the recesses around the liver?

Answer 48

hepatorenal recess and subphrenic recess