Abdomen: Abdominal Wall, Hernias, Peritoneum

Question 1

Layers of the abdominal wall: anterolateral

Answer 1

Skin
Camper's Fascia (fatty)
Scarpa's Fascia (membranous)
External oblique
Internal oblique
Transversus abdominis
Transversalis fascia
Extra peritoneal fascia
Parietal peritoneum

Question 2

Layers of the abdominal wall: posterior

Question 3

Muscles of the anterior abdominal wall

Answer 3

Rectus abdominis
Pyramidialis
External oblique
Internal oblique
transversus abdominis

Question 4

Rectus abdominis

Answer 4

Long paired muscle. Split in 2 by linea alba. Muscles is intersected by fibrous strips, tendinous intersections. Giving rise to ‘6-pack’ shape.
Origin: crest of pubis
Insertion: diploid process, costal cartilage ribs 5-7
Innervation: Thoracoabdominal nerves (T7-T11
Function: depresses the ribs

Question 5

Internal oblique

Answer 5

Origin: inguinal ligament, iliac crest, lumbodorsal fascia
Insertion: ribs 10-12
Innervation: thoracoabdominal nerves (T7-T11), subcostal nerve, branches of lumbar plexus
Function: compresses abdominal cavity, ipsilateral rotation of torso

Question 6

External oblique

Answer 6

Origin: ribs 5-12
Insertion: iliac crest, pubic tubercle
Innervation: thoracoabdominal nerves (T7-T11) and subcostal nerve (T12)
Function: contralateral rotation of torso

Question 7

Transversus abdominis

Answer 7

Origin: inguinal ligament, costal cartilage 7-12, iliac crest, thoracolumbar fascia
Insertion: conjoint tendon, xiphoid process, linea alba, pubic crest
Innervation: thoracoabdominal nerves (T7-T11), subcostal nerve (T12), branches of lumbar plexus
Function: compression of abdominal cavity

Question 8

Pyramidalis

Answer 8

Origin: pubic crest and pubis symphysis
Insertion: linea alba
Innervation: subcostal n. (T12)
Function: tenses linea alba

Question 9

Linea alba

Answer 9

Midline of abdomen

Formed from the aponeuroses of external oblique, internal oblique, transverse abdominis

Question 10

Rectus sheath

Answer 10

Formed by the aponeurosis of external oblique, internal oblique and transverses abdominis

Question 11

Linea semilunaris

Answer 11

Formed from the lateral border of rectus abdominis

Question 12

Superficial fascia of abdominal wall

Answer 12

Above umbilicus: single sheet

Below umbilicus: superficial: Camper’s fascia and deep: Scarpa’s fascia

Question 13

Camper’s Fascia

Answer 13

Superficial fatty layer of fascia

Question 14

Scarpa’s fascia

Answer 14

Deep membranous later of fascia

Question 15

Incisions into the abdomen

Answer 15

Midline
Paramedian
Pararectal
Gridiron
Lanz
Pfannenstiel
Transverse
Kocher, Rooftop (Chevron), Mercedes-Benz
Rutherford-Morrison

Question 16

Midline incision

Answer 16

Xiphisternum to pubis symphasis (or any length along this plane)
Layers: skin, camper’s, Scarpa’s, linea alba, transversales fascia, extra-peritoneal fascia, parietal peritoneum

Question 17

Gridiron incision

Answer 17

Centred over McBurney’s point (2/3 distance between umbilicus & ASIS)
Layers: skin, Camper’s, Scarpa’s, external oblique, internal oblique, transversus abdominis, transversals fascia, extra-peritoneal facia, parietal peritoneum
Risk of injury to ilioinguinal and iliohypogastric nerves
Arc can be extended anteriorly and laterally to form Rutherford-Morrison (to access ascending bowel)

Question 18

Lanz incision

Answer 18

Inferior to the Gridiron incision

High risk of severing the ilioinguinal and ilihypogastric nerves

Question 19

Pfannenstiel incision

Answer 19

Curvilinear incision is made through skin and subcutaneous fat. Longitudinal incision is made through linea alba.

Question 20

Kocher Incision

Answer 20

Parallel to subcostal margin on right
Used to access liver and biliary tree. Used of open cholecystectomy.
Mirrored on contralateral side to create Rooftop/Chevron incision. Extended down midline to create Mercedes Benz incision.
Risk of injuring superior epigastric vessels. Lateral extension risks damage to intercostal nerves.

Question 21

Types of Hernia

Answer 21

Indirect inguinal 
Direct inguinal
Femoral 
Umbilical
Epigastric
Spigelian
Obturator
Lumbar

Question 22

Borders of the inguinal canal

Answer 22

Anterior wall: aponeurosis of external oblique, reinforced by internal oblique laterally
Posterior wall: transversalis fascia
Roof: transversals fascia, internal oblique, transversus abdominis
Floor: inguinal ligament, thickened medially by the lacunar ligament

Question 23

Openings of the inguinal canal

Answer 23

Deep (internal) ring

Superficial (external) ring

Question 24

Deep (internal) ring

Answer 24

Midpoint of inguinal ligament
Lateral to epigastric vessels
Created by transversalis fascia

Question 25

Superficial (external) ring

Answer 25

End of the inguinal canal Superior to pubic tubercle Triangle shaped opening Formed by the evagination of external oblique

Question 26

Contents of the inguinal canal

Answer 26

Spermatic cord (males only) Round ligament (females only) Ilioinguinal nerve Genital branch of genitofemoral n.

Question 27

Coverings of the spermatic cord

Answer 27

External spermatic fascia: derived from scarpa's fascia Cremaster muscle and fascia: derived from internal oblique Internal spermatic fascia: derived from transversalis fascia

Question 28

Contents of the spermatic cord

Answer 28

``` Vessels: Testicular artery Cremasteric artery and vein Artery to vas deferens Pampiniform plexus of testicular veins ``` Nerves: Genital branch of genitofemoral nerve Autonomic nerve fibres Others: Vas deferens Processus vaginalis Lymph vessels (drain to para-aortic)

Question 29

Inguinal ligament

Answer 29

Formed from external oblique aponeurosis | Runs from pubic tubercle to ASIS

Question 30

indirect inguinal hernia

Answer 30

80% | Bowel enters inguinal canal via deep inguinal ring

Question 31

Direct inguinal hernia

Answer 31

20% | Bowel enters inguinal canal directly through weakness in posterior wall, termed Hesselbach's triangle

Question 32

Borders of Hesselbach's Triangle

Answer 32

Medial: lateral border of Rectus abdominis muscle Lateral: inferior epigastric vessels Inferior: inguinal ligament

Question 33

Muscles of the posterior abdominal wall

Answer 33

Erector Spinae Quadratus Lumborum Psoas Major Psoas Minor Iliac

Question 34

Fascia of the posterior abdominal wall

Answer 34

Psoas fascia | Thoracolumbar fascia: Posterior, middle, anterior

Question 35

Psoas Major

Answer 35

Insertion: Vertebral bodies of T12-L4, transverse process of L1-L5 Insertion: ileopsoas tendon on lesser trochanter of hip Action: flexion of hip, lat rotation of thigh Innervation: anterior ramp of spinal nerves (L1-3) Blood supply: lumbar branch of olio lumbar artery

Question 36

Iliacus

Answer 36

Origin: iliac fossa Insertion: lesser trochanter of femur Action: hip flexion Innervation: femoral nerve (L1-3) Blood supply: iliolumbar, circumflex iliac, obturator, femoral

Question 37

Erector Spinae

Answer 37

3 muscles: Iliocostalis, Longissimus, Spinalis (lateral to medial: I like standing)