ANAT - Abdominal Wall + Testes

Question 1

internal oblique

Answer 1

• runs in ‘hands on chin’ direction
• if contracting unilaterally: ipsilateral lumbar rotation and lateral flexion
• if contracting bilaterally: trunk flexion (leaning forward)

Question 2

external oblique

Answer 2

• runs in ‘hands in pockets’ direction
• if contracting unilaterally: contralateral trunk rotation and ipsilateral lateral flexion
• if contracting bilaterally: trunk flexion (bend forward)

Question 3

transversus abdominis muscle

Answer 3

• runs horizontally
• functions for core stability and abdominal compression

Question 4

rectus abdominis

Answer 4

• has tendinous separations
• linea alba runs down the middle
• linea semilunaris is on either side of the muscle
• functions for lumbar flexion and core stability

Question 5

what is the rectus sheath and what is it formed by?

Answer 5

• fibrous covering enclosing rectus abdominis and pyramidalis
• formed by aponeuroses of internal oblique, external oblique and transversus abdominis

Question 6

superficial fascia

Answer 6

• superficial to external oblique
• 2 layers: camper’s fascia (fatty) and scarper’s fascia (membranous)

Question 7

blood supply to the anterior abdominal wall

Answer 7

• superior epigastric vessels: originate from internal thoracic vessels
• inferior epigastric vessels: originate from external iliac vessels
• these anastomose and supply the rectus abdominis and overlying skin

Question 8

umbilical folds

Answer 8

• median (x1): obliterated urachus (connection from bladder to umbilicus)
• medial (x2): obliterated umbilical arteries
• lateral (x2): inferior epigastric vessels

Question 9

lumbar triangle boundaries

Answer 9

• anterior: external oblique
• posterior: latissimus dorsi
• inferior: iliac crest

Question 10

superficial + deep inguinal ring origins

Answer 10

• superficial: formed from aponeurosis of external oblique parting from the pubic tubercle to form a ring shape
• deep: formed from transversalis fascia

Question 11

conjoint tendon

Answer 11

• comprises of internal oblique and transversus abdominis
• attaches to pectineal line of pubis

Question 12

inguinal canal contents

Answer 12

• runs from deep inguinal ring (formed by transversalis fascia) to the superficial inguinal ring (formed by external oblique)
• runs obliquely from lateral to medial
• transmits spermatic cord (males), round ligament of the uterus (females) and ilioinguinal nerve (both)

Question 13

inguinal canal borders

Answer 13

• roof: internal oblique and transversus abdominis (conjoint tendon)
• anterior wall: internal oblique and external oblique aponeurosis
• posterior wall: internal oblique and transversus abdominis (conjoint tendon)
• floor: inguinal ligament

Question 14

direct vs indirect inguinal hernia

Answer 14

• indirect: congenital - passes thru inguinal canal (lateral to inferior epigastric vessels) - usually on the scrotum
• direct: acquired - pushes through a weak spot in the posterior wall of inguinal canal (medial to inferior epigastric vessels) - usually superolateral to scrotum

Question 15

how are the testes attached to the scrotum posteriorly + clinical significance

Answer 15

• mesentery (mesorchium)
• if this is too long it can result in torsion (twisting) of the testis - sits horizontally instead of obliquely and cuts off blood supply
• prehn’s sign: pain worsens with testicular elevation b/c doesn’t fix underlying ischaemia

Question 16

where do the testes originate?

Answer 16

• posterior abdominal wall and then descend into pelvic cavity as gubernaculum shortens

Question 17

spermatic cord layers from superficial to deep

Answer 17

• skin (scrotum)
• dartos fascia (from scarpa’s fascia)
• external spermatic fascia (from ext. oblique)
• cremaster muscle and fascia (from int. oblique)
• SKIPS transversus abdominis bc ends too superiorly
• internal spermatic fascia (from transversalis fascia)
• tunica vaginalis (from peritoneum)

Question 18

implications of ectopic testes

Answer 18

• sperm not kept in the right conditions = can lead to cancer due to rapid cell division

Question 19

abdominal wall layers (lateral to semilunar line)

Answer 19

• skin
• superficial fascia (superficial = camper’s/fatty fascia, deep = scarpa’s/membranous fascia)
• external oblique (hands in pockets)
• internal oblique (hands on chin)
• transversus abdominis
• transversalis fascia
• extraperitoneal fat
• parietal peritoneum

Question 20

abdominal wall layers (medial)

Answer 20

• skin
• superficial fascia (superficial = camper’s/fatty fascia, deep = scarpa’s/membranous fascia)
• rectus sheath
• pyramidalis
• rectus abdominis
• transversals fascia
• extraperitoneal fat
• parietal peritoneum

Question 21

umbilical folds

Answer 21

• folds of peritoneum over certain structures, on anterior abdominal wall
• median umbilical fold (most medial): contains median umbilical ligament (remnant of urachus - connects bladder to umbilicus)
• medial umbilical fold (x2): contains medial umbilical ligament (remnant of obliterated umbilical arteries)
• lateral umbilical fold (most lateral): contains inferior umbilical vessels which still function

Question 22

how do you derive the lines that make the 9 abdominal regions?

Answer 22

• two vertical lines are midclavicular
• superior horizontal line (subcostal plane) = inferior border of 10th costal cartilage
• inferior horizontal line (trans tubercular plane) = L5

Question 23

difference in innervation of testes vs scrotum

Answer 23

• testes = autonomic (sympathetic = testicular plexus and parasympathetic = vagus n)
• scrotum = somatic (anterior = ilioinguinal and genitofemoral, posterior = pudendal)

Question 24

clinical significance of the arcuate line

Answer 24

• above the arcuate line: rectus abdominis is surrounded both anteriorly (external and internal oblique) and posteriorly (internal oblique and transversus abdominis) by rectus sheath aponeuroses
• below the arcuate line: rectus abdominis only has an anterior rectus sheath (all 3 aponeuroses)
• therefore spigelian (lateral ventral) hernias are more likely to occur below the arcuate line due to the lack of posterior support

Question 25

what is the arcuate line

Answer 25

- 1/3 between umbilicus and pubic symphysis - bottom most transverse line of the rectus abdominis

Question 26

incarcerated vs strangulated hernia

Answer 26

- incarcerated: non-reducible b/c tissue becomes trapped and can't be pushed back in - strangulated: loss of blood supply to herniated tissue - these are both non-reducible

Question 27

borders of inguinal triangle and clinical relevance

Answer 27

- inferior: inguinal ligament - medial: lateral border of rectus abdominis - lateral: inferior epigastric vessels

Question 28

gubernaculum remnant for males vs females

Answer 28

- males: scrotal ligament (anteriorly), testicular ligament and ligament of the epididymis (posteriorly) - females; round ligament of the uterus and ovarian ligament

Question 29

varicocele

Answer 29

- abnormally enlarged veins - 'bag of worms' sign

Question 30

main vasculature of the GIT

Answer 30

- superior epigastric vessel: branch off internal thoracic artery - inferior epigastric vessels: branch off external iliac artery

Question 31

bell clapper deformity

Answer 31

- when the tunica vaginalis (peritoneum) attaches high on the spermatic cord - testes can move more freely > torsion = ischaemia and necrosis

Question 32

difference between testicular and scrotal cancer clinically?

Answer 32

- scrotum lymph nodes drain superficially (inguinal lymph nodes) so cancer is more palpable in inguinal region if enlarged - testes lymph nodes drain deeply (para-aortic lymph nodes) due to origin in posterior abdominal wall so cancer not palpable until it reaches L supraclavicular node