abdominal wall and hernia Flashcards
anterolateral walls
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
sheet like muscles
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
external oblique muscle
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
internal oblique muscle
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.
transverse abdominis muscle
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
result of the sheet muscles
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
rectus abdominis
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
function of the rectus abdominis
work with antero-lateral abdominal wall muscles
flexors of the lumber spine
location of the rectus abdominis
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
rectus sheath
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
The abdominal lining
deep to the transverse abdominis muscle is a fibrous layer called transversalis fascia
deep to this is parietal peritoneum
epigastric vessels
lie deep to the muscle
there is an anastomosis between superior epigastric arteries from internal thoracic, and the inferior ones from the external iliac
nerve supply to the muscles
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
definition of a hernia
the protrusion of a viscus through a defect from its containing compartment in an abnormal position
components of a hernia
sac - neck, body and fundus
maybe contents eg bowel, omentum, bladder
coverings
defect in containing compartment
types of hernia
inguinal hernias, indirect and direct
femoral hernia
incisional hernia
umbilical hernia
why is inguinal canal a site of hernias
site of weakness
especially in male
when combined with factors that increase intra-abdominal pressure can lead to herniation
types of aetiology of hernia
congenital or acquired
congenital hernia
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
acquired hernia
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
borders of the inguinal canal
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
treatment of an inguinal hernia
conservative or surgical
conservative treatment for hernia
identify risk factors eg asthma, COPD and constipation and treating them
surgical treatment for the hernia
define anatomy
define, inspect and exercise hernial sac
close the defect
repair should be tension free
superficial fascia
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
femoral hernia
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
