This document provides an overview of the anatomy and components of the ventral abdominal wall and hernias. It discusses: 1) The boundaries and layers of the abdominal wall including skin, subcutaneous tissue, fascia, muscles and tendons. The main muscles discussed are the rectus abdominis, pyramidalis, external and internal oblique, and transversus abdominis. 2) The blood supply, nerve innervation and lymphatic drainage of the abdominal wall. 3) Classification systems for incisional hernias and the pathophysiology of ventral wall hernias related to increases in intra-abdominal pressure. 4) Different types of hernias including

1. VENTRAL WALL
HERNIA PART I
BYDRRAZIABANOO
(FNBMASSCHOLAR)

2. Anatomy of the abdominal wall
Its a hexagonal area bounded
Superiorly-xiphoid process and the
costal margins
Inferiorly- the iliac crest, the inguinal
ligaments and superior edge of the
pubic bone and pubic symphysis
Lateral extension occurs posteriorly
to the erector spinous and quadratus
lumborum muscle adjacent to the
lumbar spine.

3. COMPONENTS
The abdominal wall is composed of skin, muscles and fascia.the muscles
are divided into midline and anterolateral groups of muscle The RECTUS
ABDOMINIS and THE PYRAMIDALIS muscle comprises the midline group
and the bilateral anterolateral groups are composed of trilaminar
structure consisting of the EXTERNAL OBLIQUE MUSCLE, THE INTERNAL
OBLIQUE MUSCLES and THE TRANSVERSUS ABDOMINIS MUSCLES.
In addition to this there are numerous tendinous structures and
delineations including the line alba ,linea semicircularis.

4. SKIN
SUBCUTANEOUS LAYER
it contains fat, cutaneous nerves, cutaneous vessels and superficial
lymphatics.Below the level of umbilicus fascia is divided into a superficial
fatty layer(fascia of camper) and a deep membranous layer (fascia of
scarpa). Most part of the fascia is a single layer that contains variable
amount of fat.

5. CUTANEOUS NERVES ARTERIES AND VEINS
• Nerve supply; lower six thoracic nerves and by the first lumbar nerve.
• Anterior cutaneous arteries are branches of superior and inferior epigastric
artery and accompany the anterior cutaneous nerves.
• Lateral cutaneous arteries are branches of the lower intercostals arteries and
accompany the lateral cutaneous nerves.
• Superficial epigastric, superficial external pudendal, superficial circumflex
iliac artery arise from the femoral artery and supply the skin of the lower part of
abdomen.
• The venous drainage is by superficial epigastric, superficial external pudendal,
superficial circumflex iliac vein which drains into femoral vein.

6. ANTERIOR ABDOMINALWALLMUSCLES

7. RECTUS ABDOMINIS MUSCLE
Origin: arises from two tendinous heads. The lateral
head arises from the lateral part of pubic crest, the
medial head from the anterior pubic ligament.
insertion:xiphoid process, 5th, 6th and 7th costal
cartilage.
Nerve supply:lower six or seven thoracic spinal
nerves.
Action;
• Flexion of the trunk (flexion of thoracic and lumber
spine), while it works by drawing pubic symphysis
and sternum toward each other.
• Tense the anterior wall of the abdomen and assist in
compressing the contents of the abdomen
• It works on posterior pelvic tilt with other abdominal
muscles.
• Play a role in core stability.

8. THE PYRIMIDALIS MUSCLE
It is a rudimentary muscle in human beings. This is a small triangular
muscle arising from anterior surface of body of pubis. Fibers pass
upwards and medially to be inserted into linea alba.
The nerve supply is from the Subcostal nerve which is the ventral ramus
of the twelfth thoracic spinal nerve.

9. THE EXTERNAL OBLIQUE MUSCLE:
• Origin: the outer surface of the shaft of the lower eight ribs
• insertion:it inserts into the xiphoid process,along the whole length of the linea
alba and extends to the pubic crest and the pectineal line; lower fleshy fibers to
the outer lip of the iliac crest
• innervation:by lower six thoracic nerves and the subcostal nerve
• Action: contributes in forming the anterior abdominal wall
rotation and flexion of the trunk
bending from side to side
stabilizing the core

11. INTERNAL OBLIQUE MUSCLE
Origin: along the whole length of the lumbar fascia, from the anterior two-thirds of
the intermediate line of the iliac crest and from the lateral two-thirds of the grooved
upper surface of the inguinal ligament
insertion: into the inferior border of the costal cartilages of the lower 3 ribs (10th-
12th) in continuity with the internal intercostal muscles becomes aponeurotic at the
level of the 9th costal cartilage, which fuses at the midline at the linea alba.
innervation: lower intercostal nerves (T7-T12), ilioinguinal and iliohypogastric
nerves
action: compression of abdominal content, forced expiration, flexes and bends the
trunk

13. TRANSVERSUS ABDOMINIS MUSCLE
Origin: thoracolumbar fascia, inner lip of the anterior two-thirds of the iliac
crest and costal cartilages of 7th-12th ribs where it interdigitates with fibers of
the diaphragm.
Insertion:into the anterior aponeurosis,the linea alba and pubic crest
Innervation: intercostal nerves (T7-T11), subcostal nerve (T12), iliohypogastric
nerve (L1), ilioinguinal nerve (L1)
Blood supply: posterior intercostal and subcostal
arteries, superior and inferior epigastric arteries, superficial and
deep circumflex iliac arteries, posterior lumbar arteries
Action: flat muscle which forms part of abdominal wall, compresses abdominal
cavity

15. DEEP ARTERIES AND VEINS OF
ANTERIOR ABDOMINAL WALL
Arterial supply: superior epigastric and
musculophrenic artery above, inferior
epigastric and deep circumflex iliac
artery below, small branches of lower
two or three posterior intercostal,
subcostal and lumbar arteries,
superficial epigastric, circumflex.
Venous drainage : superior epigastric and
musculophrenic vein above and inferior
epigastric and deep circumflex iliac vein
below.

16. Linea alba ; literally translated as the white line ,it is a completely fibrous
structure composed of collagen and elastin traversing from the xiphoid
process to the pubic symphysis ,its width varies among population
between 15-22mm along its course ,widest just above the umbilicus and
narrowest at both extremes.its formed as the aponerosis of the EOM,IOM
& TAM merge terminally in the midline bisecting the rectus muscle .

18. Rectus sheath
The rectus sheath extends between the inferior costal margin and costal cartilages of 5th
-7th ribs superiorly,and the pubic crest inferiorly.It is a tough fibrous compartment
formed by the aponeuroses of the transverse abdominalmuscle, and
the internal and external oblique muscles. It contains the rectus
abdominis and pyramidalis muscles, as well as vessels and nerves.
ARCUATE LINE:The arcuate line, also known as the semicircular line of Douglas,is a
curved line found posterior to the rectus abdominismuscle bilaterally, between the
umbilicus and the pubic symphysis.This anatomical finding may not always be present,
and its exact positionmay vary.

19. ANSARI CLASSIFICATION FOR ARCUATE LINE ;
• CLASSICAL ARCUATE LINE; Here the distance between the umbilicus
and the arcuate line ranges from 3cm – 6.5cm.
• HIGH ARCUATE LINE; if the distance is less than or equals to 3 its called
high arcuate line.
• LOW ARCUATE LINE: if the distance from the umlicus is more than 6.5cm
its called as low arcuate line.

20. Above arcuate line;
At the lateral border of the rectus abdominismuscle, the aponeurosisof the internal
oblique muscle splits into an anterior layer and a posteriorlayer .An anterior rectus
sheath composed of the aponeurosisof the external oblique muscle and anterior portion
of the aponeurosisof the internal oblique muscle passes in front of the rectus abdominis
muscle. A posteriorrectus sheath composed of the posterior portion of the aponeurosis
of the internal oblique muscle and the aponeurosis of the transversus abdominis
passes behind the rectus abdominis muscle.
Below the arcuate;
The aponeuroses of all three muscles (includingthe transversus)pass in front of the
rectus. The posterior layer of the rectus sheath is thus absent and the rectus abdominis
muscle is separated from the peritoneum only by the transversalisfascia.

21. The semilunar line, linea semilunaris or Spigelian line:
It is a bilateral vertical curved line in the anterior abdominal wall where
the layers of the rectus sheath fuse lateral to the rectus abdominis muscle
and medial to the oblique muscles.

24. Hernia is defined as an abnormal protrusion of a
viscous or a part of it through a weakness or gap in the
abdominal wall, which may be acquired or natural with
a sac covering it.

25. Etiology of ventral wall HERNIAS
• Conditions increasing intra abdominal pressure;straining at stool,
obesity ,ascites,copd,BPH,pregnancy,heavy lifting
• Connective tissue disorders; Ehler Danlos syndromr,osteogenesis
imperfecta,Marfan syndrome
• Trauma
• Surgery
• t2DM
• Immunosuppresion
• Chronic smokers
• Erect posture
• Congenital hernias

26. Incisionsal hernia
Pre operative factors;
• age>60 years
• malnutrition
• sepsis/shock
• diabetic
• steroid
• peritonitis
• anaemia

27. Intra operative factors
• Type of surgery: emergency surgeries,stoma reversal
• prolonged surgery
• vertical incision
• operations involving bowel
• expertise of operating surgeon
• increase blood loss
Post operative factors
• wound site infection
• mechanical ventilation
• Post operative ileus
• coughing

29. Pathophysiology of ventral wall hernia;
• the abdominopelvic cavity is a cylinder enveloped by muscles tendons
and bony structures.
• If intra abdominal pressure > abdominal wall pressure, the wall ruputure
at the weakest point causing herniation based on Laplace law which
states in an elastic spherical vessel the tension pressure wall thickness
and diameter are related by
tension= (diameter* pressure)
-------------------------------
(4* wall thickness)

30. Classification of hernia

31. EHS CLASSIFICATION OF
INCISIONAL HERNIA

32. Umblical Hernia: the umblical defect
is present at birth but closes as the
stump of the umblical cord heals
within a week of birth
.Umblical hernia in children;occurs
in upto 10% of infants more in
premature babies.
.Umblical hernias in adults; usually
occurs due to increase intra
abdominal pressure such as obesity
pregnancy ascites etc

33. • Epigastric hernia: they usually are
smaller hernias and begin as transverse
split in the midline raphe and are usually
<1cm in size and are elliptical in shape
and contains extraperitoneal fat as
content.
• Spigelian Hernia:they arise through a
defect in the spigelian fascia and may
advance through the internal oblique to
spread out deep to the external oblique
aponeurosis.

34. Lumbar hernias
• They are relatively rare, more common in males and are twice as common on the left than
the right side.
• Patients are usually between 50 to 70 years old.
• These hernias can occur anywhere within the lumbar region but are more common through
the superior lumbar triangle (of Grynfeltt-LesshaftThe inferior lumbar triangle (of Petit.
Lumbar hernias have been classified as congenital (20%) or acquired (80%).
• If acquired, they may be primary (55%) or secondary following trauma, surgery or
inflammation (25%)

35. The superiorlumbar triangle (of Grynfeltt-
Lesshaft)
◦ Boundaries
• medially: the quadratus lumborum muscle
• superiorly: twelfth rib
• laterally: internal oblique muscle
• floor: transversalisfascia and the
aponeurosis of the transversus abdominis
muscle of the abdomen
• roof: external oblique and latissimusdorsi
muscles
The inferior triangle of ( petit)
◦ Boundaries
• inferiorly: iliac crest
• anteriorly: external oblique muscle
• posteriorly:latissimus dorsi muscle
• floor: internal oblique muscle

36. Parastomal hernia:Parastomal
hernia is a type of incisional
hernia occurring in abdominal
integuments in the vicinity of a
stoma, i.e. a condition wherein
abdominal contents, typically the
bowel or greater omentum,
protrude through abdominal
integuments surrounded by the
hernia sac at the location of
formed stoma.

37. Investigation and evaluation
The presentation of an abdominal wall hernia is usually pain, swelling or
fullness at the site of occurrence that can change with position or
Valsalva. In some cases when a hernia is incarcerated or strangulated, the
enlargement may be erythematous or cause an asymmetry. In
most cases, the diagnosis of an abdominal hernia can be made by history
and physical exam but severe obesity, which is a major risk factor, can
limit the exam.

38. Ultasonography;
for occult small hernis
obese patients
recurrent hernias
incisional hernias
complex hernias
Advantages of USG;
inexpensive
Non invasive
No radiation
Portable

39. DYNAMIC ABDOMINAL SONOGRAPHY FOR HERNIA(DASH)
the technique uses a 12-MHz linear ultrasound probe in five sequential
cranial to caudal passes of the ventral abdominal wall to detect even
small fascial defects
its sensitivity is 98% ans specificity of around 88%.

40. COMPUTED TOMOGRAPHY
Due to its rapid image acquisition, demonstration of fine morphologic
detail, 3-D reconstructability and reproducibility, CT is generally the most
popular imaging modality for the evaluation of ventral abdominal hernias.
Relatively cheaper
Excellent anatomical delineation
Permitts visualization of the whole abdomen
Good Spatial resolution
Superior temporal resolution

42. CT SCAN OF ABDOMEN

46. Component separation index;On
the axial CT slice that shows the
hernia orifice at its widest, lines
are drawn from the medial edges
of the rectus abdominis
muscles to meet at a point on the
anterior wall of the aorta. The
angle between these two lines is
the angle of diastasis. The
component separation index is
the angle of diastasis divided by
360° 2
Values above 0.21 tend to
increase the likelihood of
requiring interpositional mesh
repair.

47. Carbonell equation
If the RDR(rectus to defect ratio) is > 2, routine
surgical repair will be able to close the abdominal
wall defect in 90% of cases.
If the RDR is < 1.5, in more than 52% of the repairs,
additional component separation technique is
required.
◦ Image I
In this patient the Rectus to Defect Ratio: (49 mm +
43 mm) / 157 mm = 0.58.
This ratio predicts that hernia closure will probably
not be possible without performing a component
separation technique
◦ Image 2;In a different patient, the Rectus to Defect
Ratio is: (73 mm + 81 mm) / 51 mm = 3.
Contrary to the previous case, hernia closure will be
possible without performing a component separation
technique.

48. MAGNETIC RESONANCE IMAGING
Compared to CT, MRI offers the advantage of direct multiplane imaging
without ionizing radiation and the use of contrast agents. A relative merit
of MRI is the excellent demonstration of abdominal wall layers.
It can be used in patients where ct scan is contraindicated.
Concomittent pelvic pathologies.
Demerits;
• contraindicated in patients with
metallic prosthesis
claustrophobia
• long scan timing
• expensive

49. Thank you