The Anterior Abdominal Wall

Question 1

The anterior abdominal wall can be divided into…

Answer 1

… anterolateral and posterior sections

Question 2

Functions of the AAW

Answer 2

• Support, protection, anti-gravity maintenance
• Assists in forceful expiration by pushing the abdominal viscera upwards.
• Is involved in any action (coughing, vomiting, defecation) that increases intra-abdominal pressure.

Question 3

The anterolateral abdominal wall consists of four main layers (external to internal)…

Answer 3

Skin
Superficial fascia
Muscles
Associated fascia
Parietal peritoneum

Question 4

Superior borders of the AAW

Answer 4

Costal cartilages 7-12
Xiphoid process
Level of 10th cartilage, L3

Question 5

Inferior borders of the AAW

Answer 5

Pubic bones and iliac crests at L4

Umbilicus

Question 6

The abdominal quadrants are formed by…

Answer 6

… two intersecting lines at the umbilicus, running from the xiphoid process to the pubic symphysis and across the umbilicus

Question 7

What are the planes of the abdominal regions?

Answer 7

• 2 Mid-clavicular planes (vertical)
• Transpyloric plane (horizontal)
• Intertubercular plane (horizontal)

Question 8

The transpyloric plane is found…

Answer 8

…halfway between the jugular notch and pubic symphysis, above the umbilicus.

Question 9

The intertubercular plane is formed by…

Answer 9

The tubercles of the iliac crests

Question 10

The filled urinary bladdder lies in…

Answer 10

The hypogastric region

Question 11

The cutaneous nerves of the AAW are derived from…

Answer 11

…the ventral rami of T7 through L1.

Question 12

Direction of the cutaneous nerves of the AAW

Answer 12

They pass inferiomedially in plane between the transverse and internal oblique muscles

Question 13

Layers of the abdominal wall from superficial to deep:

Answer 13

• Skin
• Superficial fascia
• Deep superficial fascia
• Muscles
• Transversalis fascia
• Extraperitoneal fat (extraperitoneal fascia)
• Peritoneum

Question 14

How many muscles make up the AAW?

Answer 14

5 - TIRE P(ump)

Question 15

Superficial fascia above the umbilicus

Answer 15

It is a single sheet of connective tissue, continuous with the superficial fascia in other regions of the body.

Question 16

Superficial fascia below the umbilicus

Answer 16

It is divided into two layers; the fatty superficial layer (Camper’s fascia) and the membranous deep layer (Scarpa’s fascia).

Question 17

The muscles of the anterolateral abdominal wall can be divided into

Answer 17

two main groups: flat and vertical

Question 18

In the anteromedial aspect of the abdominal wall, each flat muscle forms an…

Answer 18

…aponeurosis (a broad, flat tendon), which covers the vertical rectus abdominis muscle.

Question 19

The linea alba is formed by…

Answer 19

…the aponeuroses of all the flat muscles becoming entwined in the midline to form a fibrous structure

Question 20

Properties of external oblique

Answer 20

• The largest and most superficial flat
• ## Its fibres run inferomedially (pocket)

Question 21

Origin and insertion of external oblique

Answer 21

Originates from ribs 5-12, and inserts into the iliac crest and pubic tubercle.

Question 22

Innervation of the abdominal muscles

Answer 22

Thoracoabdominal nerves (T7-T11) and subcostal nerve (T12), except pyramidalis that’s just subcostal

Question 23

Properties of Internal Oblique

Answer 23

• lies deep to the external oblique
• smaller and thinner in structure
• fibres running superomedially (inverted pocket).

Question 24

Origin and insertion of internal oblique

Answer 24

Originates from the inguinal ligament, iliac crest and lumbodorsal fascia, and inserts into ribs 10-12.

Question 25

Transversus abdominis properties

Answer 25

- Deepest of the flat muscles | - Transversely running fibres.

Question 26

Deep to the transversus abdominis muscle is...

Answer 26

... a well-formed layer of fascia, known as the transversalis fascia.

Question 27

Origin and insertion of transversus abdominis muscle

Answer 27

Originates from the inguinal ligament, costal cartilages 7-12, the iliac crest and thoracolumbar fascia. Inserts into the conjoint tendon, xiphoid process, linea alba and the pubic crest.

Question 28

Origin and insertion of rectus abdominis

Answer 28

Originates from the crest of the pubis, before inserting into the xiphoid process of the sternum and the costal cartilage of ribs 5-7

Question 29

Location of pyramidalis

Answer 29

Superficial and inferior to the rectus abdominis.

Question 30

Apex and base of pyramidalis

Answer 30

Base - on the pubis bone | Apex - attached to the linea alba.

Question 31

The anterior wall of the rectus sheath is formed by...

Answer 31

...the aponeuroses of the external oblique, and of half of the internal oblique.

Question 32

The posterior wall of the rectus sheath is formed by...

Answer 32

...the aponeuroses of half the internal oblique and of the transversus abdominis.

Question 33

At what point of the AAW is there no rectus sheath?

Answer 33

Approximately midway between the umbilicus and the pubic symphysis, where all the aponeuroses move to the anterior wall of the rectus sheath. At this point, there is no posterior wall to the sheath; the rectus abdominis is in direct contact with the transversalis fascia.

Question 34

The demarcation point where the posterior layer of the rectus sheath ends is called...

Answer 34

...the arcuate line.

Question 35

Arterial supply above the umbilicus

Answer 35

``` Superior and inferior epigastric Musculophrenic Subcostal Lumbar 1-4 Posterior intercostal ```

Question 36

Arterial supply below the umbilicus

Answer 36

Superficial epigastric Superficial circumflex iliac Superficial external pudendal

Question 37

Below the umbilicus, the superficial veins of the AAW drain into...

Answer 37

...the femoral venous system via the great saphenous

Question 38

Above the umbilicus, the superficial veins of the AAW drain into...

Answer 38

...the azygous venous system