anterior abdominal wall W6

Question 1

anterolateral abdominal wall muscles and the direction of their fibres?

Answer 1

rectus abdominus (vertical)
external oblique (downward and forward)
internal oblique (upward and forward)
transversus abdominis (transverse)

Question 2

origin and insertion of external oblique?

Answer 2

origin - lower 8 ribs

insertion - Linea alba (via rectus sheath), iliac crest, lower border forms inguinal ligament

Question 3

origin and insertion of internal oblique?

Answer 3

origin - thoracolumbar fascia, iliac crest, lateral two-thirds of inguinal ligament

insertion - costal margin, linea alba (via rectus sheath), pubic crest + pectineal line (via conjoint tendon)

Question 4

origin and insertion of transversus abdominis?

Answer 4

origin - costal margin, thoracolumbar fascia, iliac crest, lateral one-third of inguinal ligament

insertion - linea alba (via rectus sheath), pubic crest + pectineal line (via conjoint tendon)

Question 5

origin and insertion of rectus abdominus?

Answer 5

origin - pubic crest

insertion - costal cartilages 5, 6, 7

Question 6

what muscle layers does the neurovascular plane lie between

Answer 6

between inner and middle layers of the body wall:

internal oblique and transversus abdominus in abdomen

internal and innermost intercostal in thorax

Question 7

what are the nerve supplies of the anterolateral abdominal wall muscles?

Answer 7

lower 6 thoracic spinal nerves (T7-T12) + iliohypogastric and ilioinguinal (L1) for the fibres of the conjoint tendon (“inguinal shutter mechanism”)

Question 8

what are the actions of the anterolateral abdominal wall muscles?

Answer 8

move trunk (flexion, lateral rotation)
compress abdomen (expiration, evacuation)
support of viscera
control of inguinal shutter mechanism

Question 9

what is the linea alba? why is it clinically relevant?

Answer 9

the midline fibrous structure running from xiphisternum to pubic symphysis

bloodless plane - therefore midline incision common in surgery

Question 10

3 levels of the rectus sheath?

Answer 10

above costal margin
below arcuate line
inbetween these

Question 11

what is the arrangement of the aponeurosis of the anterolateral abdominal wall at this level: above the costal margin?

Answer 11

anterior sheath only (from EO aponeurosis)

Question 12

what is the arrangement of the aponeurosis of the anterolateral abdominal wall at this level: between the costal margin and the arcuate line

Answer 12

anterior and posterior sheath (note the splitting of the IO aponeurosis)

Question 13

what is the arrangement of the aponeurosis of the anterolateral abdominal wall at this level: below the arcuate line

Answer 13

anterior sheath only (from all 3 aponeuroses)

Question 14

what does the rectus sheath contain

Answer 14

rectus abdominus +/- pyramidalis
superior and inferior epigastric vessels
lower 6 intercostal nerves (T7-T12) and accompanying vessels

Question 15

in a midline incision, what layers would be traversed before reaching the abdominal cavity?

Answer 15

Skin
Superficial fascia (fatty layer of Camper, membranous layer of Scarpa)
Linea alba
Transversalis fascia
Extraperitoneal fat
Parietal peritoneum

Question 16

what does the inguinal canal contain

Answer 16

spermatic cord in male
round ligament of uterus in female
ilioinguinal nerve
obliterated remains of the processus vaginalis

Question 17

from where are the coverings of the spermatic cord derived?

Answer 17

external spermatic fascia - from EO aponeurosis

cremasteric fascia - from IO and TA muscles

internal spermatic fascia - from transversalis fascia

Question 18

what are the contents of the spermatic cord?

Answer 18

3 arteries (testicular, cremasteric, artery of vas)

3 nerves (ilioinguinal, genital branch of genitofemoral, sympathetic fibres)

3 others (corresponding veins including pampiniform plexus, lymphatics, vas deferens)

obliterated remains of processus vaginalis

Question 19

what structures form the anterior wall of the inguinal canal?

Answer 19

superficial ring (medially; weak)
EO aponeurosis and IO muscle (laterally; strong)

Question 20

what structures form the posterior wall of the inguinal canal?

Answer 20

conjoint tendon (medially; strong)
transversalis fascia and deep ring (laterally; weak)

Question 21

what structures form the roof of the inguinal canal?

Answer 21

lowermost fibres of IO and TA muscles (insert via conjoint tendon, form inguinal shutter)

Question 22

what structures form the floor of the inguinal canal?

Answer 22

inguinal and lacunar ligaments

Question 23

what is a hernia?

Answer 23

protrusion of an organ or tissue from its normal position into an abnormal position

Question 24

what does the term groin hernia include

Answer 24

inguinal hernias
femoral hernias

Question 25

what structure is located at the mid-point of inguinal ligament? where is this?

Answer 25

indicates position of deep ring.
midway between ASIS and pubic tubercle

Question 26

what structure is located at the mid-inguinal point?

Answer 26

indicates position of femoral artery
midway between ASIS and pubic symphysis

Question 27

difference between direct and indirect inguinal hernias?

Answer 27

direct - through the posterior wall (medial to inferior epigastric vessels)

indirect - through inguinal canal (lateral to inferior epigastric vessels)

Question 28

what are the boundaries of the inguinal triangle of Hesselbach and why is it useful to define?

Answer 28

inguinal ligament, inferior epigastric vessels, edge of rectus sheath (linea semilunaris)

a direct inguinal hernia pushes forward through the triangle (medial to the IEA)

Question 29

indirect inguinal vs femoral?

Answer 29

inguinal - above and medial to pubic tubercle

femoral - below and lateral to pubic tubercle