abdominal wall and hernia

Question 1

anterolateral walls

Answer 1

3 layers
control pressure and vol in abdomino-pelvic (peritoneal) cavity
contract these muscles and relaxation of the diaphragm pushes the dome of the diaphragm further into the chest cavity and so compresses the lungs
most important muscles In deep, rapid, or forced expiration
simultaneous contraction of sheet muscles and diaphragm increase the intra-abdominal pressure - mechanism for expelling contents of the abdomino-pelvic organs = expulsive functions

Question 2

sheet like muscles

Answer 2

external oblique
internal oblique
transversus abdominis 
arrangement similar to ICM 
originate from the margins of the anterolateral wall, turn into aponeuroses (sheet like tendons) in anterior abdominal wall and insert into fibrous band called linea alba that extends from the xiphoid process to the pubic symphysis

Question 3

external oblique muscle

Answer 3

arises by slips from the superficial surface of the lower eight ribs - interlocking with teb slips of the serratus anterior and latissimus dorsi and anterior half of the iliac crest
has a free posterior border
fibres run antero-inferiorly and its aponeurosis blends with linea alba
free lower border runs in a straight line from anterior superior iliac spine to pubic terbucle - inguinal ligament
femoral nerve, artery and vein enter the thigh by passing deep into inguinal ligament

Question 4

internal oblique muscle

Answer 4

originate from the lumbar fascia, the anterior two-thirds of the iliac crest and the lateral two-thirds of the inguinal ligament
muscle fibres fan - high ones reach inferior border of rib 10-12 but the lowest descend to the crest and medial part of the pectineal line of the pubis
aponeurosis inserts into the linea alba.

Question 5

transverse abdominis muscle

Answer 5

runs medially from the deep aspect of the costal margin at ribs 7 -12, the lumbar fascia, the anterior two-thirds of the iliac crest and the lateral third of the inguinal ligament, to become aponeurotic anteriorly, and blends into the linea alba.
low fibres insert on the pubic crest and the pectineal line with the lower part of oblique muscle as the conjoint tendon

Question 6

result of the sheet muscles

Answer 6

over the antero lateral abdominal wall, muscle and collagen fibres of the 3 layers run in opposite directions - prevent herniation of abdominal contents
all run in nearly same dirn near the inferior wall border of the wall

Question 7

rectus abdominis

Answer 7

4th muscular component of the anterior abdominal wall
paired vertically running muscles separated by linea alba
each rectus arises from costal cartilages 5-7 nad xiphoid process
descends lateral to linea alba
inserts into supero-anterior surface of the pubic symphysis
narrow as they descend
divided into segments by transverse tendinous intersections - give 6 pack

Question 8

function of the rectus abdominis

Answer 8

work with antero-lateral abdominal wall muscles

flexors of the lumber spine

Question 9

location of the rectus abdominis

Answer 9

deep to the aponeurosis of external oblique throughout its length
In the upper two-thirds of the anterior abdominal wall it lies anterior to the transversus aponeurosis while the internal oblique aponeurosis splits to enclose it.
lies in fibrous tunnel called rectus sheath

Question 10

rectus sheath

Answer 10

anterior wall of the sheath consists of aponeurosis of external oblique fused with anterior leaf of the internal oblique aponeurosis
lower part of sheath - all the aponeuroses pass anterior to rectus - this part is backless
The free lower posterior margin of the posterior layer of the rectus sheath is known as the arcuate line
lateral margin of the rectus abdominis the aponeuroses of 3 flat muscles fuse to form linea semilunaris before enclosing the rectus muscle and fusing again in the midline at the linea alba

Question 11

The abdominal lining

Answer 11

deep to the transverse abdominis muscle is a fibrous layer called transversalis fascia
deep to this is parietal peritoneum

Question 12

epigastric vessels

Answer 12

lie deep to the muscle
there is an anastomosis between superior epigastric arteries from internal thoracic, and the inferior ones from the external iliac

Question 13

nerve supply to the muscles

Answer 13

from T6-L1
intercostal nerves T6-T11 and subcostal nerve T12 enter abdo wall at ends of the ribs passing deep into costal cartilages - close the intercostal spaces
main trunks lie between the internal oblique and transverse layers

Question 14

definition of a hernia

Answer 14

the protrusion of a viscus through a defect from its containing compartment in an abnormal position

Question 15

components of a hernia

Answer 15

sac - neck, body and fundus
maybe contents eg bowel, omentum, bladder
coverings
defect in containing compartment

Question 16

types of hernia

Answer 16

inguinal hernias, indirect and direct
femoral hernia
incisional hernia
umbilical hernia

Question 17

why is inguinal canal a site of hernias

Answer 17

site of weakness
especially in male
when combined with factors that increase intra-abdominal pressure can lead to herniation

Question 18

types of aetiology of hernia

Answer 18

congenital or acquired

Question 19

congenital hernia

Answer 19

descent of the testes requires processus vaginalis - finger like projection of parietal peritoneum
foetal structure normally closes - persistently patent processus vaginalis is a indirect inguinal hernial sac

Question 20

acquired hernia

Answer 20

increased intra-abdominal pressure can exploit a weak abdominal wall
because of inguinal canal
or because of weakening of tissues with age, fatty infiltration associated with obesity or increase in circulating elastases that have been postulated as a weak abdominal musculature

Question 21

borders of the inguinal canal

Answer 21

floor - inguinal ligament
rolled under inferior edge of the external oblique aponeurosis
anterior wall - external oblique aponeurosis reinforced reinforced by internal oblique muscle fibres laterally
posterior wall - transversalis fascia, reinforced by conjoint tendon medially
roof - aching fibres of internal oblique and transversus abdominis muscle fibres

Question 22

treatment of an inguinal hernia

Answer 22

conservative or surgical

Question 23

conservative treatment for hernia

Answer 23

identify risk factors eg asthma, COPD and constipation and treating them

Question 24

surgical treatment for the hernia

Answer 24

define anatomy
define, inspect and exercise hernial sac
close the defect
repair should be tension free

Question 25

superficial fascia

Answer 25

has superficial fatty layer - fascia of Camper, contain nerves and vessels
including superficial epigastric veins
and a deep membranous layer of fascia of scarpa that is continuous with deep fascia (fascia lata) of the thigh below the inguinal ligament
in midline - membranous layer of superficial fascia form sheath around the penis (or clitoris) and an investment around the scrotum or labia majora
However, the superficial fatty layer is found only in the female mons pubis and labia major

Question 26

femoral hernia

Answer 26

passes through femoral canal and into the medial aspect of the anterior thigh
femoral canal lies at the medial edge of the femoral sheath
femoral sheath contains the femoral artery, femoral vein and lymphatics
teh neck of femoral canal is narrow and is prone to trapping bowel in sac
therefore this hernia is irreducible and susceptible to bowel sstrangulation
usually acquired
mainly in middle aged and elderly individuals
more common in women because women have wider pelvises than men