ICL 1.2: Introduction to the Abdominal Wall

Question 1

what is the anterolateral abdominal wall?

Answer 1

a multilayered musculofibrous sheet anchored to the skeleton of the trunk and forms the anterior and lateral walls of the abdominal cavity

Question 2

what are the functions of the abdominal wall?

Answer 2

1. forms a firm, flexible wall which keeps theabdominal viscerain the abdominal cavity
2. protectsthe abdominal viscera from injury
3. maintains theanatomical positionof abdominal viscera against gravity
4. assists inforceful expirationby pushing the abdominal viscera upwards
5. bend and rotate trunk
6. support trunk
7. raises the intraabdominal pressure –> loud speech, vomiting, defection, child birth

Question 3

what are the abdominal surface landmarks?

Answer 3

1. xiphoid process
2. costal margin
3. tip of the 9th costal cartilage
4. tendinous intersection
5. umbilicus
6. iliac crest
7. anterior superior iliac spine
8. linea semilunaris
9. linea alba
10. inguinal ligament
11. pubic tubercule
12. pubic crest
13. pubic symphysis

Question 4

what is the differential diagnosis for pain or swelling in the right lower quadrant?

Answer 4

FIRST POSSIBILITY
1. appendix

2. cecum
3. terminal ileum
4. ascending colon
5. right kidney
6. right ureter
7. iliacus & psoas muscles
8. sacroiliac joint

SECOND POSSIBILITY
remote organ referring pain to RLQ (right ureter) or normally remote organ but ectopically present in the RLQ (right kidney)

THIRD POSSIBILITY
remote organ enlarged enough to reach the RLQ (liver or spleen)

Question 5

what can cause referred pain to the abdominal wall?

Answer 5

pain from internal viscera projects to the abdominal wall in a specific manner and location which may be used to identify viscus causing the pain

slide 7, go look

Question 6

why study the anterior abdominal wall?

Answer 6

1. the anterior abdominal wall is where you can inspect, palpate and auscultate the abdominal viscera (abdominal physical exam)
2. pain from internal viscera projects (referred) to the abdominal wall in a specific manner and location which may be used to identify viscus causing the pain
3. anterior abdominal wall shows the telltale signs of internal diseases
4. abdominal wall has the disease of it’s own: hernias
5. abdominal wall is your gateway to surgically access abdominal visceral where you can explore, remove , transplant and repair

Question 7

what are the layers of the abdominal wall?

Answer 7

1. parietal peritoneum (inner most)
2. extraperitoneal fat
3. fascia transversalis
4. transversus abdominis muscle
5. internal oblique muscle
6. external oblique muscle
7. deep membranous layer of superficial fascia = Scarpa’s fascia
8. superficial fatty layer of superficial fascia = Camper’s fascia
9. skin (outer most)

Question 8

what are the 4 muscles of the anterior abdomen wall?

Answer 8

1. external oblique
2. internal oblique
3. transversus abdominis
4. rectus abdominis

Question 9

what are the general features of the muscles of the anterior abdominal wall?

Answer 9

1. they have no bony reinforcement
2. they are formed of 3 sheet-like layers
3. they are continuous with layers of intercostal muscles
4. muscle fibers of different layers run in different directions for strength

Question 10

what is the origin and insertion of the external oblique muscle?

Answer 10

origin: arises from the external surface of the lower 8 ribs (5-12)
insertion: xiphoid process, lineament alba, symphysis pubis, pubic crest, pubic tubercle, ASIS, outer lip of the anterior half of the iliac crest

Question 11

what direction are the fibers of the external oblique?

Answer 11

the fleshy fibers run downward and medially and become aponeurotic mid-way between the origin and insertion, and the aponeurosis inserts into the xiphoid process, lineament alba, symphysis pubis, pubic crest, pubic tubercle, ASIS, outer lip of the anterior half of the iliac crest

Question 12

what is the linea alba?

Answer 12

as the aponeurotic fibers of the external oblique in both sides meet at the midline, they interdigitate to form the strong midline structure called linea alba

the linea alba receives the aponeurotic insertion of the internal oblique and transversus abdominis

the linea alba extends from the xiphoid process to pubic symphysis

Question 13

how does the external oblique contribute to the inguinal canal?

Answer 13

the lower aponeurotic insertion of the external oblique between the pubic tubercle and anterior superior iliac spine has no bony attachment which means it forms a free border termed the inguinal ligament

the lower part of the aponeurosis of external oblique above the inguinal ligament forms the anterior wall of the inguinal canal

above the medial end of the inguinal ligament (superolateral to the pubic tubercle) there is a gap in the aponeurosis of the external oblique, forming the superficial inguinal ring (the external opening of the inguinal canal)

so basically the external oblique contributes to the anterior wall, inguinal ligament, superficial inguinal ring and floor of the inguinal canal

Question 14

what forms the floor of the inguinal canal?

Answer 14

the lower aponeurotic insertion of the external oblique between the pubic tubercle and anterior superior iliac spine has no attachment which means it forms the free border which is slightly thickened to form the inguinal ligament

this free margin is rolled in to form a groove or gutter-like structure, and this groove will form the floor of the inguinal canal

Question 15

what is the origin and insertion of the internal oblique?

Answer 15

origin: Lateral third of inguinal ligament
Iliac crest, thoracolumbar fascia, internal surface of the lower 6 (7th-12th) ribs

the fibers of the internal oblique runs transversely and medially to insert into:

xiphoid process, lineament alba, symphysis pubis, pubic crest and pectin pubis

Question 16

how does the traverses abdomens contribute to the inguinal canal?

Answer 16

…?

Question 17

what is the transversalis fascia?

Answer 17

it’s a thin sheet of fascia covering the internal surface of the transversus abdominis muscle

it forms a continuous layer of fascia covering the internal surface of the abdominal cavity outside the extraperitoneal fat

superiorly, it fuses with the fascia covering the under surface of the diaphragm

posteriorly, it is continuous with the anterior layer of thoracolumbar fascia covering the anterior surface of the posterior abdominal wall and with the iliac fascia covering iliacus muscle

so basically the transversalis fascia forms the posterior wall of the inguinal canal and the deep inguinal ring

Question 18

what is the origin and insertion of the rectus abdominis?

Answer 18

origin: it arises from the symphysis pubis and pubic crest

inserts into the costal cartilages of the 5th-7th ribs

Question 19

what is the lineament semilunaris?

Answer 19

a curvedtendinous linefound on either side of therectus abdominis muscle

each corresponds to the lateral border of the rectus abdominis, extends from thecartilageof the ninthribto thepubic tubercle, and is formed by theaponeurosisof the internal obliqueat its line of division to enclose the rectus muscle

Question 20

what is the arcuate line?

Answer 20

the crescent shaped inferior border of the posterior layer of rectus sheath

it’s located approximately 1/3 of the distance from the umbilicus to the pubic crest

posterior to the rectus abdominis m. there is no rectus sheath inferior to the arcuate line

Question 21

what is the inguinal region?

Answer 21

the lower area of the abdominal wall below a line connecting the Rt and Lt anterior superior iliac spines to the inguinal ligaments

clinical significance: it has the inguinal canals and it is the site for direct and indirect inguinal hernias

Question 22

what is the inguinal canal? what’s its function during development?

Answer 22

an oblique passage through the lower part of the anterior abdominal wall between the deep and superficial inguinal rings

it lies (2-4cm) above and parallel to the medial half of the inguinal ligament

during development, it serves as a route of passage for the testes from the posterior abdominal wall to the scrotum

Question 23

what is the superficial inguinal ring?

Answer 23

an opening in external oblique aponeurosis, superolateral to pubic tubercle

Question 24

what is the deep inguinal ring? what are its contents?

Answer 24

an opening in the transversalis fascia one and half inch above the midpoint of the inguinal ligament

Question 25

what are the contents of the inguinal canal?

Answer 25

it contains spermatic cord in males | and round ligament of the uterus in females.

Question 26

what are the walls of the inguinal canal?

Answer 26

anterior: aponeurosis of external oblique posterior: fascia transversalis floor: Inguinal ligament roof: the arching fibers from the very beginning of the origins of the internal oblique and transversus abdominis to the very end of the their insertions

Question 27

what is the spermatic cord?

Answer 27

a group of structures | passing from deep to superficial inguinal ring

Question 28

what are the components of the spermatic cord?

Answer 28

1. ductus deferens 2. testicular artery 3. testicular vein (pampiniform plexus of veins) 4. lymph vessels 5. autonomic nerves 6. remains of the processus vaginalis 7. cremastric artery 8. artery to ductus deferens 9. genital branch of genitofemoral nerve

Question 29

what are the coverings of the spermatic cord?

Answer 29

1. internal spermatic fascia (yellow), derived from transversalis fascia 2. cremastric muscle and fascia (pink), derived from internal oblique 3. external spermatic fascia (grey), derived from external oblique

Question 30

what are the landmarks of the internal surface of the anterior abdominal wall?

Answer 30

1. umbilicus 2. arcuate lines 3. lateral inguinal fossa 4. deep inguinal ring 5. inguinal ligament

Question 31

what are the arteries of the anterior abdominal wall?

Answer 31

the arteries supplying the anterior abdominal wall are derived from, internal thoracic, posterior intercostal, external iliac and femoral arteries: 1. superior epigastric (from internal thoracic) ``` 2. musculophrenic (from internal thoracic) Inferior epigastric (from external iliac) ``` 3. deep circumflex iliac (from external iliac) 4. superficial circumflex iliac (from femoral) 5. superficial epigastric (from femoral) 10th, 11th. posterior intercostal 6. subcostal artery. with the exception of the superficial epigastric and superficial circumflex iliac which are subcutaneous, the others run between the internal oblique and transversus abdominis. The superior and inferior epigastric run between the rectus abdominis and posterior wall of the rectus sheath

Question 32

what's the venous drainage of the anterior abdominal wall?

Answer 32

named arteries are accompanied by veins which drains into the equivalent of the parent arteries in addition: the lateral thoracic vein, a tributary of the axillary vein, forms with superficial epigastric, a tributary of the great saphenous vein, and periumbilical veins longitudinal venous channel connecting the superior vena cava, inferior vena cava and portal vein which provide a away for collateral venous return in case of obstruction of any major internal vein

Question 33

what is caput medusa?

Answer 33

when the veins of the anterior abdominal wall get enlarged during cirrhosis of the liver

Question 34

what is the cutaneous nerve supply of the anterior abdominal wall?

Answer 34

it's derived from the lateral and anterior cutaneous branches of the thoracoabdominal nerves (T7-T11), subcostal nerve, Iliohypogastric and ilioinguinal nerves

Question 35

what's the innervation of the muscles of the anterolateral abdominal wall?

Answer 35

Thoracoabdominal nerves T7-T11 intercostal nerves Subcostal nerve T12 Iliohypogastric and ilioinguinal nerve (L1) from lumbar plexus.

Question 36

the anterior wall of the inguinal canal is formed by which of the following structure? A. rectus abdominis B. external oblique C. anterior wall of rectus sheath D. internal oblique E. transversus abdominis

Answer 36

B. external oblique

Question 37

to make a paramedian abdominal incision at the site indicated by brown line to expose the rectus abdominis muscle, you need to cut through all of the following structures except: A. skin, superficial fascia and Scarpa’s fascia B. aponeurosis of external oblique C. aponeurosis of internal oblique D. aponeurosis of transversus abdominis E. transversalis fascia

Answer 37

E. transversalis fascia

Question 38

during laparoscopic hernia repair surgery, which of the following structure is used to distinguish direct from indirect inguinal hernia? A. inguinal ligament B. medial inguinal fold C. lateral inguinal fold D. median inguinal fold E. none of the above

Answer 38

C. lateral inguinal fold

Question 39

which of the following bony structures is important landmark to locate the superficial inguinal ring? A. anterior superior iliac spine B. pubic symphysis C. pectineal line D. pubic tubercle E. pubic crest

Answer 39

D. pubic tubercle

Question 40

which of the following statements is not true about the deep inguinal ring? A. Is located in the transversalis fascial B. is one and half an inch above the mid point of inguinal ligament C. it admits the ilioinguinal nerve D. It admits the genital branch of genitofemoral nerve E. It admits the testicular artery

Answer 40

C. it admits the ilioinguinal nerve

Question 41

which nerve of the following is at risk during hernia repair surgery? A. subcostal nerve B. femoral nerve C. T10 D. obturator nerve E. ilioinguinal nerve

Answer 41

E. ilioinguinal nerve

Question 42

the integrity of which of the following structure is most important in preventing the occurrence of the direct inguinal hernia? A. rectus abdominis muscle B. posterior wall of the inguinal canal C. conjoint tendon D. anterior wall of the inguinal canal E. tight superficial inguinal ring

Answer 42

C. conjoint tendon

Question 43

to make a paramedian abdominal incision at the site indicated by brown line to expose the rectus abdominis muscle, you need to cut through all of the following structures except: A. skin, superficial fatty layer of superficial fascia (Camper’s) fascia B. deep membranous layer of superficial fascia (Scarpa’s fascia) C. aponeurosis of external and internal obliques D. aponeurosis of transversus abdominis E. both B and D

Answer 43

E. both B and D