Lecture 8: Anterior Abdominal Wall & Inguinal Region

Question 1

What are the margins of the abdomen?

Answer 1

ASIS, costal margin, iliac crest, pubic tubercle

Question 2

What are the anterior abdominal wall layers?

Answer 2

Skin
Superficial fascia (campers-fatty, scarpals-membranous)
External oblique
Internal oblique
Transversus abdominus
Trasversali fascia
Exztraperitoneal fat
Parietal peritoneum

Question 3

What is the relationship of the 3 anterior ab wall muscles to the costal margin?

Answer 3

External overlaps, internal edge to edge, transversus underlaps

Question 4

What are the features of the external oblique?

Answer 4

Free inferior edge is inguinal ligament - asis to pubic tubercle - meets anteriorly at linea alba

Question 5

What are the features of the internal oblique?

Answer 5

Arches to insert onto pubic crest and lateral 2/3 attaches to inguinal ligament

Question 6

What are the features of transversus abdominus?

Answer 6

Arches to insert onto pubic crest with internal oblique - CONJOINED TENDON - lateral 1/3 attaches to inguinal ligament

Question 7

What is the midline muscle and what are its features?

Answer 7

• Rectus abdominus
• Wider as it ascends to attach to pec major
• Tendinous intersections at umbilicus, xiphoid and halfway between these points
• Enclosed within a sheath

Question 8

What makes up the rectus sheath?

Answer 8

Upper - external and half of internal go anterior, half of internal and transversus go posterior

Lower - all 3 muscles layers are aponeurotic medially so this fascia goes across anteriorly, no posterior sheath

Question 9

At what point does the lower part of the rectus sheath start?

Answer 9

Halfway between umbilicus and pubic crest

Question 10

What muscle layers does the neuromuscular bundle run through?

Answer 10

Internal oblique and transversus abdominus

Question 11

What arteries supply these muscles and what are they branches of?

Answer 11

Superior (internal thoracic), superficial (femoral) and inferior (external iliac) epigastric

Question 12

What is the venous drainage of the abdomen?

Answer 12

Systemic and hepatic drainage

Question 13

What are the extensions of the inguinal ligament?

Answer 13

Pectineal - along pectineal line

Lacunar - crescent shaped, inwards to pectineal line

Question 14

Where do testes develop?

Answer 14

Extraperitoneal fat on posterior abdominal wall

Question 15

When are testes in pelvis and when are they in the inguinal canal?

Answer 15

Week 12 and week 28

Question 16

What is the pathway of the testes?

Answer 16

• Deficiency in transversus abdominus: deep inguinal ring
• arching fibres of internal and transversus
• along inguinal ligament
• Triangular opening in external oblique: superficial inguinal ring
• scrotum

Question 17

What are the boundaries of the inguinal canal?

Answer 17

Floor- inguinal ligament
Roof - arching fibres of internal oblique and transversus abdomens
Anterior - external oblique and internal oblique
Posterior- transversalis fascia, conjoined tendon

Question 18

What fascia is the spermatic cord encased in?

Answer 18

Internal (transversals fascia), cremasteric (cremaster muscle), external (aponeurosis of external oblique)

Question 19

What is the function of the cremaster muscle?

Answer 19

Retract testes back into body

Question 20

What causes a hernia?

Answer 20

Chronic intra-abdominal pressure, weakness in abdominal wall

Question 21

What is a bilateral indirect inguinal hernia?

Answer 21

Protrusion through inguinal canal due to deficiency in fascia transversalis (congential abnormality - incomplete closure of pocket - processus vaginalis)

Question 22

What is a bilateral direct inguinal hernia?

Answer 22

Due to weak abdominal wall muscles - pushing forward