Anterior Abdominal Wall & Inguinal Region

Question 1

What direction are the fibres of the external oblique?

Answer 1

anteroinferior (follow external intercostals)

Question 2

What is the origin of the external obliques?

Answer 2

anterior surface of the lower 8 ribs

edge to edge with pec major and serratus anterior

Question 3

What is the insertion of the external obliques?

Answer 3

medially: linea alba/vertical raphae
posteriorly: free
inferiorly: anterior half of the iliac crest, ASIS, pubic tubercle, and pubic crest

Question 4

What are the 3 free edges of the external oblique?

Answer 4

superior aponeurotic edge (origin of pec +)

free posterior edge

inferior edge between the ASIS and the pubic tubercle (inguinal ligament)

*triangular opening between pubic tubercle and pubic crest*

Question 5

What is the orientation of the internal oblique fibres?

Answer 5

back pockets/ posteroinferior

(follow internal intercostals)

Question 6

What is the origin of the internal oblique?

Answer 6

thoracolumbar fascia (posterior)

anterior 2/3rds iliac crest/lateral 2/3rds of inguinal ligament (free edge of external oblique)

Question 7

What is the insertion of the internal oblique?

Answer 7

costal margin

linea alba

conjoin tendon to pubic crest w/transversus abdominus

Question 8

What is the origin of transversus abdominus?

Answer 8

deep surface of costal margin (continuous with diaphragm)

thoracolumbar fascia

anterior 2/3rds of iliac crest

lateral 1/2 of inguinal ligament

Question 9

What is the insertion of transversus abdominus?

Answer 9

linea alba

conjoin tendon to pubic crest w/internal oblique

Question 10

What is the origin of rectus abdominus?

Answer 10

body & crest of pubis

Question 11

What is the insertion of rectus abdominus?

Answer 11

anterior surface of costal cartilages 5, 6, & 7

Question 12

What is the arcuate line?

Answer 12

end of posterior rectus sheath, ~2.5cm below the umbilicus

Question 13

What is the innervation of the anterior abdominal wall?

Answer 13

ventral rami of T7- L1:

T7-T9 above umbilicus

T10 umbilicus

T11-12 below umbilicus

L1 groin

Question 14

What is the arterial supply of the anterior abdominal wall?

Answer 14

superior epigastric (internal thoracic)

anastamoses with

inferior epigastric (external iliac)

in the posterior recuts sheath

*superficial epigastric lies in superficial fascia*

Question 15

Venous drainage of the anterior abdominal wall is by

Answer 15

superficial and deep veins accompanying arteries

drain into portal or caval circulation

Question 16

What is the lacunar ligament?

Answer 16

medial reflection of the inguinal ligament (before attachment at the pubic tubercle) to the pectineal line

Question 17

What is the pectineal ligament?

Answer 17

runs on pectineal line of the pubic bone

extension of the lacunar ligament

Question 18

Gonads develop

Answer 18

in the extraperiotneal fat of the superor lumbar region of the posterior abdominal wall

Question 19

What is the deep inguinal ring?

Answer 19

opening in the transversalis fascia (passage of testis)

halfway between the ASIS & the pubic tubercle

fingers breadth above the inguinal ligament

Question 20

What is the superficial/external inguinal ring?

Answer 20

triangular opening in external oblique in its attachment between the pubic tubercle and pubic crest

(passage of testis & spermatic cord)

Question 21

What forms the floor of the inguinal canal?

Answer 21

inguinal ligament

Question 22

What forms the roof of the inguinal canal?

Answer 22

arching fibres of internal oblique & transversus abdominus

Question 23

What forms the anterior wall of the inguinal canal?

Answer 23

external oblique aponeurosis, lateral internal oblique

Question 24

What forms the posterior wall of the inguinal canal?

Answer 24

transversalis fascia, conjoint tendon (medially)

Question 25

Internal spermatic fascia is acquired

Answer 25

as the spermatic cord passes through the transversalis fascia

Question 26

Cremasteric fascia & muscle is acquired from

Answer 26

passage of the spermatic chord through transversalis abdominus and internal oblique

Question 27

External spermatic fascia is acquired

Answer 27

as the spermatic cord exits the external inguinal ring through external oblique

Question 28

What is an indirect inguinal hernia?

Answer 28

• most common
• passes through inguinal canal via the deep ring into the scrotum via the superficial ring
• arises from incomplete closure of the processus vaginalis

Question 29

What is a direct inguinal hernia?

Answer 29

• protrusion forward in the region of the inguinal canal through a weakness in its posterior wall
  
  • not entering the canal via the deep ring, but rather protruding into it

Question 30

What predisposes to inguinal hernias?

Answer 30

• severing the L1 fibres innervating the conjoin tendon in appendectomy
  
  • weakens ability of internal oblique to close the inguinal canal on increased intra-abdominal pressure

Question 31

What prevents chronic inguinal hernia on raised intra-abdominal pressure?

Answer 31

closure of the inguinal canal by contraction of internal and external oblique muscle fibres that comprise the roof