Ant. & Post. Abdominal Wall Muscles & Inguinal Canal

Question 1

What are the 4 anterior abdominal wall muscles?

Answer 1

1) Rectus Abdominis
2) External Abdominal Oblique
3) Internal Abdominal Oblique
4) Transverse Abdominis

Question 2

What muscles form the rectus sheath (3)?

Answer 2

1) External Abdominal Oblique
2) Internal Abdominal Oblique
3) Transverse Abdominis

Question 3

Location & fibres of External Oblique?

Answer 3

Location: Lateral, anterior side
Fibers: inferior & anterior

Question 4

External Oblique origin, insertion, nerve innervation & function?

Answer 4

O: Lower 8 ribs (external surfaces)
I: Linea alba
Pubic Tubercle
Iliac crest (anterior half)
N: Intercostal n (T7-T12)
Function:
1. Flexion of trunk
2. Contralateral Rotation
3. Compress Abdominal contents

Question 5

Location & fibres of Internal Oblique?

Answer 5

Location: Lateral, anterior side
Fibers: Superior & anterior

Question 6

Internal Oblique origin, insertion, nerve innervation & function?

Answer 6

O: Inguinal Ligament
Iliac Crest
Thoracolumbar fascia
I: Linea alba
ribs (lower 3)
N: Intercostal n. (T6 - L1)
Function:
1. Flex Trunk
2. Ipsilateral Rotation
3. Compress abdominal contents

Question 7

Transverse abdominis origin, insertion, nerve innervation & function?

Answer 7

O: Inguinal Ligament
Iliac crest
thoracolumbar fascia
ribs (cartilage - lower 6)
I: Linea alba
N: Intercostal n. (T6 - L1)
Function:
1. Compress abdominal contents

Question 8

To rotate to the right, which obliques do you use?

Answer 8

Rotation to R:
R IO (ipsilateral rotation)
L EO (contralateral rotation)

Question 9

What separates the rectus abdomen from the 3 other anterior abdominal muscles?

Answer 9

Linea alba

Question 10

What are the tendinous intersections on rectus abdomens?

Answer 10

3 fibrous bands that cross the muscle. Shortens bellies for power.

Question 11

Rectus Abdominis origin, insertion, nerve innervation & function?

Answer 11

O: Public Crest
Symphysis pubis
I: Xiphoid process
Ribs (cartilage -5,6,7)
N: intercostal n. (T6 - T12)
Function:
1. Trunk Flexion
2. Posterior pelvic tilt
3. Compress abdominal contents

Question 12

Camper’s fascia?

Answer 12

• fatty layer
  -thick superficial layer of adipose & areolar connective tissue
  -more prominent in inferior to umbilicus

Question 13

Scarpa’s fascia?

Answer 13

• deep membranous layer
  Anchored:
• laterally to the aponeurosis of the external oblique
• medially to the Linea alba of the rectus sheath

Question 14

What is the rectus sheath?

Answer 14

-durable, resilient, fibrous compartment that protects/contains rectus abdomens
-composed by the aponeurosis as they converge to form linea alba:
1. EO
2. IO
3. TA

Question 15

What is the arcuate line?

Answer 15

-half the distance between the umbilicus & pubic symphysis
-composition of rectus sheath changes here (weaker)
- inferior to this point aponeurosis of all 3 muscles pass rectus abdomens anteriorly
-thus, internal aspect off RA directly contacts transversals fascia

Question 16

Layers (7) of anterior abdominal wall in superior 2/3rds and inferior 1/3rd?

Answer 16

1. Skin
2. Camper’s fascia
3. Scarpa’s fascia
4. Rectus sheath
   -Anterior lamina
   -Posterior lamina
5. Trasversalis fascia
6. Extraperitoneal Fat
7. Parietal Perioneum

In the superior (2/3)..
Anterior lamina = Full aponeurosis of EO + anterior 1/2 of IO

Posterior lamina = Inferior 1/2 of IO + full aponeurosis of TA

In inferior 1/3..
Anterior lamina = aponeurosis of all 3 muscles (EO,IO, TA)

Posterior lamina = NO layer!

Question 17

Layers of anterolateral abdominal wall (9)?

Answer 17

1. Skin
2. Camper’s fascia
3. Scarpa’s fascia
4. External Oblique
5. Internal Oblique
6. Traversus abdominis
7. Trasversalis fascia
8. Extraperitoneal Fat
9. Parietal Perioneum

Question 18

Muscles of the posterior abdominal wall (3)?

Answer 18

1. Quadratus Lumborum
2. Psoas major
3. Iliacus

Question 19

Quadratus Lumborum origin, insertion, nerve innervation & function?

Answer 19

O: Iliac crest
Iliolumbar ligament
I: Rib 12
TVPs of L1-L4
N: Ventral (anterior) rami of spinal n. (T12-L4)
Function:
1. Extender of trunk
2. Lateral Flexion of trunk
3. Fixes rib 12 during inspiration

Question 20

Psoas major origin, insertion, nerve innervation & function?

Answer 20

O: Bodies & TVPs (L1-L5)
I: Lesser trochanter (femur)
N: Lumbar plexus (L1,2,3)
Function:
1. Flexes thigh
2. Lateral rotation of thigh
3. Flexes trunk
4. Lateral flexion of trunk

Question 21

Iliacus origin, insertion, nerve innervation & function?

Answer 21

O: Iliac crest
sacral ala
I: Lesser trochanter (femur)
N: Femoral n.
Function:
1.Flexes thigh
2. Lateral rotation of thigh

Question 22

What is the inguinal canal & what does it contain in males & females?

Answer 22

• oblique canal about 4 cm long
  -Males: Spermatic cord (vas deferens, testicular vessels, autonomic n & lymphatics) & ilioinguinal ligament
  -Females: round ligament of uterus & ilioinguinal ligament

Question 23

Superficial vs deep inguinal ring?

Answer 23

Superficial: a triangular gap in EO aponeurosis

Deep: an oval opening in fascia transversalis
-1/2 inch above midinguinal pt
-lateral to epigastric vessels

Question 24

What is the conjoint tendon?

Answer 24

-formed by lowest aponeurotic fibers of IO & TA muscles.
-lies behind superficial ligament ring
-strengthens abdominal wall there