Abdominal Wall

Question 1

What are the specific regions of the abdominal wall?

Answer 1

1. cranial abdominal region: xiphoid region to hypochondriac regions (L and R)
2. middle abdominal region: umbilical region to lateral abdominal regions (L and R)
3. caudal abdominal region: pubic region to inguinal regions (L and R)

Question 2

What are the designated names for the ventral branches of spinals nerves L1-L4?

Answer 2

T13:costoabdominal
L1: cranial iliohypogastric 
L2: caudal iliohypogastric
L3:ilioinguinal
L4: lateral cutaneous femoral

lateral cutaneous branches between skin and external abdominal oblique*

medial branches between internal abdominal oblique and transverses abdominis muscles

Question 3

What arteries act as blood supply for the four main quadrants of the abdominal wall?

Answer 3

Cranioventral: cranial epigastric artery and the superficial cranial epigastric artery

Caudoventral: caudal epigastric artery and superficial caudal epigastric artery

Craniodorsal: phrenicoabdominal artery

Caudodorsal:deep circumflex iliac artery

Question 4

What are the boundaries of the deep inguinal ring?

Answer 4

cranial boundary: caudal border of the internal abdominal oblique muscle

medial boundary: rectus abdominis

lateral and caudal boundary: inguinal ligament

Question 5

What is significant about the paralumbar fossa in the horse versus the cow/bull?

Answer 5

Horse: the RIGHT paralumbar fossa is used to access the cecum

Cow/bull: the LEFT paralumbar fossa is used to access the rumen

Question 6

origins of the cranial and caudal superficial epigastric arteries

Answer 6

internal thoracic artery –> cranial epigastric artery –> cranial superficial epigastric artery

external pudendal artery (emerges from superficial inguinal ring)–> caudal superficial epigastric artery
-originates from pudendoepigastric trunk (branch of deep femoral artery)

Question 7

external abdominal oblique

Answer 7

• originate from the ribs and thoracolumbar fascia
• caudoventral orientation (craniodorsal –> caudoventral)

-caudal border has pelvic tendon (inguinal ligament is caudal edge) and an abdominal tendon (contributes to prepubic tendon)

inguinal ligament attaches to iliopubic eminence and the pectin

Question 8

internal abdominal oblique

Answer 8

hip–> sternum; cranioventral orientation (caudodorsal–> cranioventral)

• originates from the tuber coxae, the inguinal ligament, and the thoracolumbar fascia
• inserts on aponeuroses via costal arch, rectus abdominis, linea alba, and prepubic tendon

Question 9

transversus abdominis

Answer 9

-runs transversally from transverse processes of lumbar vertebrae, thoracolumbar fascia, and inner surfaces of last ribs to linea alba

Question 10

rectus abdominis

Answer 10

• flexor of vertebral column

- extends from prepubic tendon to the sternum

Question 11

internal abdominal oblique in horse and bovine

Answer 11

Horse: originates from tuber coxae

Bovine: originates from tuber coxae, transverse process of thoracolumbar fascia and lumbar vertebrae

Question 12

What are the borders of the paralumbar fossa?

Answer 12

base: tips of the lumbar transverse processes

cranioventral border: last rib

caudoventral border: ridge formed by the internal abdominal oblique (in ox, it extends from tuber coxae to the ventral end of the last rib)

Question 13

spinal nerves of ventral branches T13-L4 in the horse

Answer 13

T18 (horse)/T13 (ox): costoabdominal
L1: iliohypogastric
L2: ilioinguinal
L3/L4: lateral cutaneous femoral and genitofemoral

Question 14

What are the components that are located in the opening of the external abdominal oblique?

Answer 14

opening for:

• superficial inguinal ring ( vaginal process/tunic, genitofemoral nerve, cremaster muscle,external pudendal artery and vein); opening between pelvic and abdominal tendons
• the muscular lacuna (iliopsoas)
• the vascular lacuna (femoral veins)

Question 15

What is the prepubic tendon? What muscles make it up?

Answer 15

• made up of aponeuroses of abdominal muscles; inserts on the left and right tendons of the rectus abdominis muscle
• strengthened by the aponeuroses of longitudinal fibers of abdominal muscles at the linea alba and the tunica flava abdominis
• inserts on the pectin of the pubis
• susceptible to rupture in pregnant mares*
• in horse, accessory ligament of the femoral head extends from prepubic tendon*