component parts of the abdominal wall

Question 1

what are the skeletal elements of the wall?

Answer 1

1. 5 lumbar vertebrae and their inter-vertebral disks
2. the superior expanded parts of the pelvic bone
3. the costal margin
4. rib XII
5. the end of rib XI and the xiphoid process

Question 2

what muscles make up the wall lateral to the vertebral column?

Answer 2

1. the quadratus lumborum
2. psoas major
3. iliacus muscle

Question 3

what’s the function and innovation of the quadratus lumborum?

Answer 3

function
-reinforce the posterior aspect of the wall
-lateral flexion and extension of vertebral column
-elevates the illium
innovation - T12, L1-L4

Question 4

what clinical significance does the quadratus lumborum have?

Answer 4

often the source of lower back pain due to stretching

between the fascia and the muscle run the twelfth thoracic, illiohypogastric and illioinguinal nerves

Question 5

what’s the function and innovation of the psoas major muscle?

Answer 5

function
-reinforce the posterior aspect of the wall
-hip flexion
innovation - anterior rami of L1-L4 (or lumbar plexus L1-L3)

Question 6

what’s the function and innovation of the iliacus muscle?

Answer 6

function
-reinforce the posterior aspect of the wall
-flexing the femur forwards
innovation - the femoral nerve

Question 7

what are, predominantly, the three main muscles of the lateral parts of the abdominal wall?

Answer 7

1. transverse abdominis (bs - subcostal arteries)
2. internal oblique (bs - subcostal arteries)
3. external oblique (bs- The cranial portion - lower intercostal arteries. Caudal portion - either the deep circumflex iliac artery or the iliolumbar artery)

Question 8

what’s the innovation and function of the transverse adbominis?

Answer 8

Thoracoabdominal (T6-T11), 
Subcostal (T12)
iliohypogastric nerve (L1)
ilioinguinal nerve (L1)
function - helps to compress the ribs and viscera, providing thoracic and pelvic stability

Question 9

what’s the innovation and function of the internal oblique?

Answer 9

Thoracoabdominal (T6-T11), 
Subcostal (T12)
iliohypogastric nerve (L1)
ilioinguinal nerve (L1)

function: 1, to act as an antagonist to the diaphragm. 2, to rotate and side bend the trunk.

Question 10

whats the innovation and function of the external oblique?

Answer 10

Thoracoabdominal nerves (T7-11)
Subcostal nerve (T12)

function: 1. pulls chest downwards to increase abdominal pressure for the valsalva maneuver. 2. rotates and bends the trunk.

Question 11

what’s the path of the subcostal arteries

Answer 11

they pass along the lower border of rib XII behind the kidney and in front of the Quadratus lumborum muscle, and is accompanied by the XIIth thoracic nerve.

Then through the posterior aponeurosis of the Transversus abdominis, and, passing forward between this muscle and the Internal Oblique, anastomoses with the superior epigastric, lower intercostal, and lumbar arteries.

Question 12

the anterior part of the wall has one muscle which spans the distance between the inferior thoracic wall and the pelvis - what is it?

Answer 12

the rectus abdominis

Question 13

what is the blood supply to the rectus abdominis

Answer 13

First, the inferior epigastric artery and vein (or veins) run superiorly on the posterior surface of the rectus abdominis, enter the rectus fascia at the arcuate line, and serve the lower part of the muscle.

Second, the superior epigastric artery, a terminal branch of the internal thoracic artery, supplies blood to the upper portion.

Finally, numerous small segmental contributions come from the lower six intercostal arteries as well.

Question 14

innovation and function of the rectus abdominis

Answer 14

segmentally by thoraco-abdominal nerves (T7 to T11)

function - forced expiration and lumbar flexion.

Question 15

at what level is the umbilicus?

Answer 15

Typically between L3-L5

Question 16

the superficial fascia (fatty connective tissue) switches from 1 to 2 layers below the umbilicus - what are the names of these layers?

Answer 16

Campers fascia and Scarpa’s Fascia

Question 17

Campers Fascia is continuous over the inguinal ligament and the superficial fascia of the thigh. in men it continues over the penis and (loosing its fat) fuses with the deep layer of superficial fascia and forms a layer of smooth muscles in around the scrotum - what is this fascias name?

Answer 17

dartos fascia

Question 18

which superficial fascia is both the most fatty and the most superficial?

Answer 18

Campers fascia

Question 19

which superficial fascia is thin and membranous?

Answer 19

Scarpa’s fascia

Question 20

which superficial fascia is firmly attached to the linea alba?

Answer 20

Scarpa’s fascia

Question 21

after the transversus abdominis muscles, what are the layers of fascia going inwards?

Answer 21

Transversalis Fascia
Extraperitoneal Fascia
Parietal Peritoneum