Anterior Abdominal Wall

Question 1

Transpyloric plane

Answer 1

L1, level of gall bladder fundus, pylorus, pancreatic neck, SMA origin, hepatic portal vein, root of transverse mesocolon, hila of kidneys

Question 2

Subcostal plane

Answer 2

Passes inferior border of 10th costal cartilage, level of transverse colon

Question 3

Transtubercle plane

Answer 3

Between iliac tubercles, level of iliocecal junction

Question 4

Interspinous plane

Answer 4

Between ASIS, level of appendix and sigmoid colon

Question 5

What is the abdominooelvic cavity?

Answer 5

Includes the abdomen and pelvis, between thoracic diaphragm and pelvic diaphragm, can extend as high as 4th intercostal space. Abdomen separated from pelvis by imaginary border of pelvic inlet (greater pelvis above pelvic inlet.)

Walls mostly bone, muscle, CT, lined by peritoneum

Question 6

What is the Anteriolateral abdominal wall?

Answer 6

Mostly muscle and aponeurosis. Upper boundary is 7-10 costal cartilages, lower boundary is inguinal ligament and pelvic bones.

Outer layer comprised ot skin, campers fascia, scarpas fascia and aponeurosis

Question 7

What is scarpa’s fascia continuous with?

Answer 7

Colle’s fascia of perineum and is fused with fascia lata of lower limb.

Note: fluid cannot go from abdominal wall into leg, but it can flow in/out of superficial perineum

Question 8

External oblique muscle

Answer 8

Runs downward in medial direction, interdigitates with serratus anterior.
Origin: outer surface of lower 6 ribs
Insertion: aponeurosis and linea alba, anterior iliac crest and pubic tubercle (lower portion rolls under to make inguinal ligament that attaches to ASIS and pubic tubercle)
Innervation: ventral rami T7-12 of intercostal nerves
Action: compress abdomen, increase intra-abdominal pressure, move trunk and retain posture

Question 9

Internal oblique muscle

Answer 9

Runs perpendicular from EO muscle
Origin: iliac crest and some of thoracolumbar fascia
Insertion: lower 10-12 ribs, aponeurosis, linea alba and pubic crest, lower part makes part of conjoint tendon (inguinal falx)
-> fibers follow spermatic cord to make cremasteric muscle
Innervation: T7-L1
Action: compress and support viscera, lateral flexes and rotates

Question 10

Transversus abdominus muscle

Answer 10

Runs transverso-medial except for some running toward pubic crest (to contribute to conjoint tendon)
Origin: lower 7-12 costal cartilages, thoracolumbar fascia, iliac crest and upper inguinal ligament
Insertion: linea alba, pecten pubic and pubic crest
Aponeurosis contributes to rectus sheath
Innervation: T7-L1
Action: Compress and support viscera

Question 11

Rectus abdominis muscle

Answer 11

Paired muscle of anterior abdominal wall; wider at top than bottom. Linea semilunaris makes up the lateral border
Origin: pubic symphysis and pubic crest
Insertion: xiphoid process and outer surface of 5-7th intercostal cartilages
Tendinous intersections form part of rectus sheath at umbilical, xiphoid and midway levels
Innervated by ventral rami T7-T12
Action: flex and compress abdomen
Pyramidis missing in 20% of population

Question 12

Rectus sheath

Answer 12

• Made of fascia and aponeurosis of muscles encompasing RA
• EO aponeurosis always anterior
• IO aponeurosis splits in upper 3/4s but is all anterior in lower 1/4
• TA aponeurosis is posterior except in lower 1/4

Question 13

Arcuate line

Answer 13

Sharp transition where all EO, IO and TA aponeuroses become anterior to rectus abdominus muscle

Below the line, rectus abdominus is in contact with transversalis fascia

Question 14

Thoraco-abdominal nerves

Answer 14

T7-T11: continuation of intercostal nerve, both motor and sensory, run between TA and IO

Question 15

Subcostal nerve

Answer 15

T12: motor runs along inferior 12th rib, sensory is superior to iliac crest

Question 16

Iliohypogastric nerve

Answer 16

L1: runs between 2nd and 3rd muscle layers; motor to IO and TA, sensory to upper inguinal and hypogastric region

Question 17

Ilioinguinal nerve

Answer 17

L1: motor lower IO and TA, sensory to lower inguinal, anterior scrotum/labia (near medial thigh)

Question 18

Superficial epigastric artery

Answer 18

Off femoral artery

Question 19

Superficial circumflex iliac artery

Answer 19

Off femoral artery, runs along inguinal ligament

Question 20

Deep circumflex iliac artery

Answer 20

Off external iliac artery, runs deep along inguinal ligament

Question 21

Inferior epigastric artery

Answer 21

Off external iliac artery, runs posterior to rectus abdominus, anastomoses with superior epigastric artery

Question 22

Superior epigastric artery

Answer 22

Terminal branch of internal thoracic artery

Question 23

Median umbilical fold

Answer 23

Obliterated urachus

Question 24

Medial umbilical fold

Answer 24

Obliterated umbilical arteries

Question 25

Lateral umbilical fold

Answer 25

Fold due to inferior epigastric artery

Question 26

Supravesicular fossa

Answer 26

Gutter on either side of upper bladder

Question 27

Medial inguinal fossa

Answer 27

Gutter lateral to medial umbilical folds

Question 28

Lateral inguinal fossa

Answer 28

Gutter lateral to lateral umbilical folds

Question 29

Where do superficial lymph vessels drain when superior to umbilicus?

Answer 29

Axillary nodes with a few going to parasternal nodes

Question 30

Where do superficial lymph vessels drain when inferior to umbilicus?

Answer 30

Superficial inguinal nodes

Question 31

Where do deep lymph vessels drain?

Answer 31

They accompany deep veins of abdominal wall

Question 32

Subcostal incision

Answer 32

2.5 cm inferior from margin, access to gall bladder and biliary tract and spleen

Question 33

Paramedian incision

Answer 33

Open anterior sheath, push rectus abdominus aside laterally and enter peritoneum

Question 34

Gridline (McBurney’s point)

Answer 34

Muscle splitting, typical of appendectomy

Question 35

Suprapubic incision

Answer 35

Used mostly in cesarian sections