1. Surgical-ANATOMY OF
ANTERIOR ABDOMINAL
WALL
Prof. M.C.Bansal
MBBS,MS,MICOG,FICOG
Professor OBGY
Ex-Principal & Controller
Jhalawar Medical College & Hospital
Mahatma Gandhi Medical College, Jaipur.

2. INTRODUCTION
• The anterior abdominal wall extends from the costal
margins and xiphoid process superiorly to the iliac crests,
pubis and pubic symphysis inferiorly.
• It overlaps and is connected to both the posterior
abdominal wall and paravertebral tissues.
• It forms a continuous but flexible sheet of tissue across
the anterior and lateral aspects of the abdomen.
• The anterior abdominal wall is made up of skin,
superficial fascia, deep fascia, muscles, extraperitoneal
fascia, and parietal peritoneum.

3. SKELETAL LANDMARKS
• The superior boundary:
• In the midline superiorly lies the
xiphoid process. From this point,
the costal margins extend to either
side from the seventh costal
cartilage to the tip of the twelth rib
• The lowest part of the costal
margin lies in the midaxillary line
and is formed by the inferior
margin of the tenth costal cartilage.

4. • The inferior boundary :
• In order, by the iliac crest, which
descends from the tubercle of the
iliac crest to the anterior superior
iliac spine; the inguinal ligament,
which runs downwards and
forwards to the pubic tubercle;
and the pubic crest, which runs
from the pubic tubercle laterally
to the pubic symphysis in the
midline.
• The postero lateral boundary is
defined by the mid axillary line.

5. LANDMARKS
1. Xiphoid process.
2. Costal margin.
3. Tip of the ninth costal
cartilage.
4. Tendinous intersections.
5. Umbilicus.
6. Iliac crest.
7. Anterior superior iliac
spine.
8. Linea semilunaris.
9. Linea alba.
10. Inguinal ligament.
11. Pubic tubercule.
12. Pubic crest.
13. Pubic symphysis.

6. ABDOMINAL PLANES
• Vertical planes :
• The midline, which passes through the xiphisternal process
and the pubic symphysis
• There are two paramedian planes which are projected from
the midclavicular line (also sometimes called the lateral or the
mammary line).
• This line passes through the midpoint of the clavicle, just
lateral to the tip of the ninth costal cartilage, and passes
through a point mid way between the anterior superior
iliac spine and the symphysis pubis.

7. • Horizontal planes :
• The transpyloric plane lies midway between the suprasternal
notch of the manubrium and the upper border of the pubic
symphysis.
• It usually lies at the level of the body of the first lumbar
vertebra .
• The hilum of both kidneys, the origin of the superior mesenteric
artery, the termination of the spinal cord, the neck, adjacent
body and head of the pancreas, and the confluence of the
superior mesenteric and splenic veins as they form the hepatic
portal vein may all lie in this plane.

8. • The transtubercular plane joins the tubercles of the iliac crests
and usually lies at the level of the body of the fifth lumbar vertebra
near its upper border.
• It indicates, the confluence of the common iliac veins and marks
the origin of the inferior vena cava.
• The xiphisternal plane runs horizontally through the xiphoid
processes at the level of the ninth thoracic vertebra. It demarcates
the level of the cardiac plateau on the central part of the upper
border of the liver.
• The subcostal plane is a line joining the lowest point of the costal
margins, formed by the tenth costal cartilage on each side. It usually
lies at the level of the body of the third lumbar vertebra, the origin of
the inferior mesenteric artery from the aorta, and the third part of
the duodenum, although this varies with posture.

9. • The supracristal plane joins the highest point of the iliac crest
on each side. It usually lies at the level of the body of the fourth
lumbar vertebra, and marks the level of bifurcation of the abdominal
aorta. On the posterior abdominal surface, it is a common level for
the identification of the fourth lumbar vertebra, and is used to
perform lumbar puncture at the L4–5 or L5–S1 intervertebral level,
which is safely below the termination of the spinal cord.
• The interspinous plane joins the centres of the anterior
superior spines of the iliac crests.
• The plane of the pubic crest lies at the level of the inferior
end of the sacrum or part of the coccyx.

10. Abdominal regions
• The abdomen can be divided into nine arbitrary regions by
the subcostal and transtubercular planes and the two
midclavicular planes projected onto the surface of the body
• The nine regions thus formed are:
• epigastrium;
• right and left hypochondrium;
• central or umbilical;
• right and left lumbar;
• hypogastrium or suprapubic;
• right and left iliac fossa.

12. SKIN OF ANTERIOR
ABDOMINAL WALL
• Loosely attached to the underlying structures except at the umbilicus,
where it is tethered to the scar tissue.
• The natural lines of cleavage in the skin are constant and run
downward and forward almost horizontally around the trunk.
• The umbilicus is a scar representing the site of attachment of the
umbilical cord in the fetus; it is situated in the linea alba and is a
common site of infections.
• If possible, all surgical incisions should be made in the lines of cleavage
where the bundles of collagen fibers in the dermis run in parallel rows.
An incision along a cleavage line will heal as a narrow scar, whereas
one that crosses the lines will heal as wide or heaped-up scars

13. Variations of abdominal skin
LINEA NIGRA STRIA GRAVIDARUM

14. INCISIONS OF ABDOMINAL
SKIN IN GYNAECOLOGY
LOWER MIDLINE
SUBUMBILICAL INCISION VERTICAL INCISION
FOR LAPAROSCOPY
PFANNENSTIEL VERTICAL
INCISION INCISION

15. Superficial Fascia
• The superficial fascia is divided into
a superficial fatty layer (fascia of
Camper) and a deep membranous
layer (Scarpa's fascia) .
SUPERFI
CIAL
MEMBR FASCIA
• The fatty layer is continuous with ANOUS
the superficial fat over the rest of LAYER
the body and may be extremely FATTY
thick (3 in. [8 cm] or more in obese LAYER
patients).
• The membranous layer is thin and
fades out laterally and above where
it becomes continuous with the
superficial fascia of the back and
the thorax, respectively.

16. • Inferiorly, the membranous layer
passes onto the front of the thigh,
where it fuses with the deep fascia
one fingerbreadth below the
inguinal ligament.
• In the midline inferiorly, the
membranous layer of fascia is not
attached to the pubis but forms a
tubular sheath for the penis (or
clitoris).
• Below in the perineum, it enters the
wall of the scrotum (or labia
majora). From there it passes to be
attached on each side to the margins
of the pubic arch; it is here referred
to as Colles' fascia.
• Posteriorly, it fuses with the perineal
body and the posterior margin of the
perineal membrane

17. Muscles of the Anterior Abdominal
Wall
• The muscles of the anterior abdominal wall consist of three broad
thin sheets that are aponeurotic in front; from exterior to interior
they are :
• The external oblique
• The internal oblique
• The transversus abdominis
• On either side of the midline anteriorly is, in addition, a wide
vertical muscle, the rectus abdominis .
• As the aponeuroses of the three sheets pass forward, they enclose
the rectus abdominis to form the rectus sheath.
• The lower part of the rectus sheath contains a small muscle called
the pyramidalis.

20. External oblique
• External oblique is the largest and the most superficial of the three
lateral abdominal muscles .
• Origin : the external surfaces and inferior borders of the lower eight
ribs.
• Insertion : Xiphoid process, linea alba, pubic crest, pubic tubercle,
iliac crest.
• Vascular supply : Branches from the lower posterior intercostal and
subcostal arteries, the superior and inferior epigastric arteries, the
superficial and deep circumflex arteries and the posterior lumbar
arteries.
• Innervation : The terminal branches of the lower five intercostal
nerves and the subcostal nerve from the ventral rami of the lower
six thoracic spinal nerves.
• Actions : External oblique contributes to the maintenance of
abdominal tone, increasing intra-abdominal pressure and lateral
flexion of the trunk against resistance.

21. Inguinal canal
• A triangular-shaped defect in the external oblique
aponeurosis lies immediately above and medial to the pubic
tubercle. This is known as the superficial inguinal ring.
• Between the anterior superior iliac spine and the pubic
tubercle, the lower border of the aponeurosis is folded
backward on itself, forming the inguinal ligament .

22. Inguinal ligament

23. Internal Oblique
• Broad, thin, muscular sheet that lies deep to the external
oblique.
• Most of its fibers run at right angles to those of the external
oblique.
• Origin : It arises from the lumbar fascia, the anterior two
thirds of the iliac crest, and the lateral two thirds of the
inguinal ligament.
• The muscle fibers radiate as they pass upward and forward.
• Insertion : The muscle is inserted into the lower borders of
the lower three ribs and their costal cartilages, the xiphoid
process, the linea alba, and the symphysis pubis.

24. • Vascular supply : Branches from the lower posterior
intercostal and subcostal arteries, the superior and inferior
epigastric arteries, the superficial and deep circumflex arteries
and the posterior lumbar arteries.
• Innervation : The terminal branches of the lower five
intercostal nerves and the subcostal nerve from the ventral
rami of the lower six thoracic spinal nerves, in addition to a
small contribution from the iliohypogastric and ilioinguinal
nerves from the ventral ramus of the first lumbar spinal nerve.
• Actions : Internal oblique contributes to the maintenance of
abdominal tone, increasing intra-abdominal pressure, and
enables lateral flexion of the trunk against resistance.

25. Lower fibres of internal oblique are joined by similar fibers
from the transversus abdominis to form the conjoint
tendon .
• As the spermatic cord (or round ligament of the uterus)
passes under the lower border of the internal oblique, it
carries with it some of the muscle fibers that are called
the cremaster muscle .

28. Transversus
• The deepest of the lateral abdominal muscles
• Its fibers run horizontally forward .
• Origin : It arises from the deep surface of the lower six costal
cartilages (interdigitating with the diaphragm), the lumbar
fascia, the anterior two thirds of inner lip of the iliac crest, and
the lateral third of the inguinal ligament.
• Insertion : It is inserted into the xiphoid process, the linea alba,
and the symphysis pubis.
• Note : the posterior border of the external oblique muscle is
free, whereas the posterior borders of the internal oblique and
transversus muscles are attached to the lumbar vertebrae by
the lumbar fascia.

29. • Vascular supply : Branches from the lower posterior
intercostal and subcostal arteries, the superior and
inferior epigastric arteries, the superficial and deep
circumflex arteries and the posterior lumbar arteries.
• Innervation : The terminal branches of the lower five
intercostal nerves, the subcostal nerve and the
iliohypogastric and ilioinguinal nerves.
• Actions : Transversus abdominis contributes mainly to
the maintenance of abdominal tone and increasing intra-
abdominal pressure.

30. Conjoint tendon
• The conjoint tendon is formed from the lower fibres of internal
oblique and the lower part of the aponeurosis of transversus
abdominis.
• It is attached to the pubic crest and pectineal line.
• It descends behind the superficial inguinal ring and acts to
strengthen the medial portion of the posterior wall of the
inguinal canal.
• The attachment to the pectineal line is frequently absent.
• Medially, the upper fibres of the tendon fuse with the anterior
wall of the rectus sheath, and laterally some fibres may blend
with the interfoveolar ligament.

32. Fascia Transversalis
• The fascia transversalis is a thin layer of fascia that lines
the transversus abdominis muscle and is continuous with
a similar layer lining the diaphragm and the iliacus
muscle .
• The femoral sheath for the femoral vessels in the lower
limbs is formed from the fascia transversalis and the
fascia iliaca that covers the iliacus muscle .

33. RECTUS ABDOMINIS
• The rectus abdominis is a long strap muscle that extends along the
whole length of the anterior abdominal wall.
• It is broader above and lies close to the midline, being separated from
its fellow by the linea alba.
• Origin : The rectus abdominis muscle arises by two heads, from the
front of the symphysis pubis and from the pubic crest.
• Insertion : It is inserted into the fifth, sixth, and seventh costal
cartilages and the xiphoid process .
• When it contracts, its lateral margin forms a curved ridge that can be
palpated and often seen and is termed the linea semilunaris. This
extends from the tip of the ninth costal cartilage to the pubic
tubercle.

34. • The rectus abdominis muscle is divided into distinct segments by
three transverse tendinous intersections: one at the level of the
xiphoid process, one at the level of the umbilicus, and one halfway
between these two. These intersections are strongly attached to the
anterior wall of the rectus sheath.
• The rectus abdominis is enclosed between the aponeuroses of the
external oblique, internal oblique, and transversus, which form the
rectus sheath.
• Vascular supply : Rectus abdominis is supplied principally by the
superior and inferior epigastric arteries
• Small terminal branches from the lower three posterior intercostal
arteries, the subcostal artery, the posterior lumbar arteries and the
deep circumflex artery may provide some contribution, particularly
to the lateral edges and the lower attachments, and they form small
anastomoses with the lateral branches of the epigastric arteries.

37. • Innervation : Rectus abdominis is innervated by the terminal
branches of the ventral rami of the lower six or seven thoracic
spinal nerves via the lower intercostal and subcostal nerves.
• Actions : The recti contribute to the flexion of the trunk. They
also contribute to the maintenance of abdominal wall tone
required during straining.
• Rectus abdominis provides an excellent myocutaneous flap,
either pedicled or free, because of the excellent vascularity
provided by the epigastric vessels and because the muscle
belly is separated from surrounding tissue within the rectus
sheath.

38. Rectus sheath
• The rectus sheath is a long fibrous sheath that encloses the
rectus abdominis muscle and pyramidalis muscle (if present) .
• The rectus sheath is formed from decussating fibres from all
three lateral abdominal muscles. External oblique, internal
oblique and transversus abdominis .

39. • Description the rectus sheath is considered at three levels :
• Above the costal margin, the anterior wall is formed by the
aponeurosis of the external oblique. The posterior wall is formed by
the thoracic wall—that is, the fifth, sixth, and seventh costal
cartilages and the intercostal spaces.
• Between the costal margin and the level of the anterior superior iliac
spine, the aponeurosis of the internal oblique splits to enclose the
rectus muscle; the external oblique aponeurosis is directed in front of
the muscle, and the transversus aponeurosis is directed behind the
muscle.
• Between the level of the anterosuperior iliac spine and the pubis, the
aponeuroses of all three muscles form the anterior wall. The
posterior wall is absent, and the rectus muscle lies in contact with the
fascia transversalis.

41. Transverse sections of the rectus sheath seen at three levels.
B. Between the of the anterior thelevel iliac spine and above the spine.
A. Above the costal margin.
C. Below the levelcostal margin and superior of the anterior superior iliac pubis

42. Rectus sheath in anterior view and in sagittal section

43. • Where the aponeuroses forming the posterior wall pass in
front of the rectus at the level of the anterior superior iliac
spine, the posterior wall has a free, curved lower border
called the arcuate line . At this site, the inferior epigastric
vessels enter the rectus sheath and pass upward to
anastomose with the superior epigastric vessels.
• The rectus sheath is separated from its fellow on the
opposite side by a fibrous band called the linea alba.

44. • Hematoma of the rectus sheath is uncommon but
important. It occurs most often on the right side below the
level of the umbilicus.
• The source of the bleeding is the inferior epigastric vein or,
more rarely, the inferior epigastric artery. These vessels
may be stretched during a severe bout of coughing or in the
later months of pregnancy, which may predispose to the
condition.
• The cause is usually blunt trauma to the abdominal wall,
such as a fall or a kick.
• The symptoms that follow the trauma include midline
abdominal pain. An acutely tender mass confined to one
rectus sheath is diagnostic.

45. DIVARICATION OF THE RECTI
• Thinning and widening of the upper linea alba may occur,
most commonly as a result of obesity or chronic straining. This
process disrupts the arrangement of the fibres of the
bilaminar aponeurosis.
• Contraction of the anterolateral abdominal muscles fails to be
transmitted across the midline through the linea alba and
increased intra-abdominal pressure causes the abdominal
viscera to protrude beneath the thinned tissue as a broad
midline bulge.
• The recti become widely separated or divaricated. There is
not a true herniation.

46. PYRAMIDALIS MUSCLE

47. Pyramidalis
• Pyramidalis is a triangular muscle that lies in front of the
lower part of rectus abdominis within the rectus sheath.
• Origin : It is attached by tendinous fibres to the front of the
pubis and to the ligamentous fibres in front of the symphysis.
• Insertion : The muscle attached medially to the linea alba.
This attachment usually lies midway between the umbilicus
and pubis, but may occur higher.
• The muscle varies considerably in size. It may be larger on
one side than on the other, absent on one or both sides, or
even doubled.

48. • Vascular supply : Pyramidalis is supplied by branches of
the inferior epigastric artery, with some contribution
from the deep circumflex iliac artery. A small artery
frequently crosses the midline posterior to the belly of
the muscle to anastomose with the contralateral vessel.
This may cause troublesome bleeding during surgical
incisions that run down as far as the lower rectus sheath
above the symphysis pubis.
• Innervation: the terminal branches of the subcostal
nerve, which is the ventral ramus of the 12th thoracic
spinal nerve.
• Actions : Pyramidalis contributes to tensing the lower
linea alba, but is of doubtful physiological significance.

49. Linea alba
• The linea alba is a tendinous raphe extending from the xiphoid
process to the symphysis pubis and pubic crest.
• It lies between the two recti and is formed by the interlacing
and decussating aponeurotic fibres of external oblique, internal
oblique and transversus abdominis.
• Below the umbilicus, the linea alba narrows progressively as
the rectus muscles lie closer together.
• Above the umbilicus, the linea alba is correspondingly broader.

50. • The linea alba has two attachments at its lower end: its
superficial fibres are attached to the symphysis pubis,
and its deeper fibres form a triangular lamella that is
attached behind rectus abdominis to the posterior
surface of the pubic crest on each side. This posterior
attachment of linea alba is named the ‘adminiculum
lineae albae'.
• The linea alba is crossed from side to side by a few
minute vessels.
• It is visible only in the lean and muscular, as a slight
groove in the anterior abdominal wall.

51. Umbiicus
• A fibrous cicatrix, the umbilicus, lies a little below the midpoint
of the linea alba, and is covered by an adherent area of skin.
• In the fetus, the umbilicus transmits the umbilical vessels,
urachus and, up to the third month, the vitelline or yolk stalk.
• It closes a few days after birth, but the vestiges of the vessels
and urachus remain attached to its deep surface.
• The remnant of the fetal left umbilical vein forms the round
ligamentum of the liver.
• The obliterated umbilical arteries form the medial umbilical
ligaments, enclosed in peritoneal folds of the same name.
• The partially obliterated remains of the urachus persist as the
median umbilical ligament.

52. Umbilical hernia
• There are three varieties of umbilical hernia:
• In true congenital herniation, a defect is present from birth.
This is usually simply the result of failure of closure of the
umbilicus after retraction of the umbilical gut loop. Less
commonly, the gut loop does not retract and remains, in part,
outside the abdominal cavity.
• An infantile umbilical hernia is caused by stretching of the
umbilical scar tissue, associated with increased intra-
abdominal pressure.
• An acquired umbilical or paraumbilical hernia actually occurs
through small areas of weakness in the linea alba, above or
below the umbilical scar.

53. Deep Fascia (FASCIA OF SCARPA)
• The deep fascia in the anterior abdominal wall is merely
a thin layer of connective tissue covering the muscles; it
lies immediately deep to the membranous layer of
superficial fascia.
• In the female, it is continued into the labia majora and
from there to the fascia of Colles.

54. Extraperitoneal Fat
•
SKIN The extraperitoneal fat is a thin layer of connective tissue that
contains a variable amount of fat and lies between the fascia
transversalis and the parietal peritoneum.
EXTRA PERITONEAL FAT
PARIETAL PERITONEUM

55. Parietal Peritoneum
• The walls of the abdomen are lined with parietal
peritoneum.
• This is a thin serous membrane and is continuous below
with the parietal peritoneum lining the pelvis .

56. Action of the muscles of the anterior and lateral
abdominal walls. Arrows indicate line of pull of different
muscles

57. NERVE SUPPLY
• The nerves of the anterior abdominal wall are:
• The anterior rami of the lower six thoracic nerves –
include the lower five intercostal nerves and the
subcostal nerves
• The first lumbar nerve - represented by the
iliohypogastric and ilioinguinal nerves, branches of the
lumbar plexus.
• They pass forward in the interval between the internal
oblique and the transversus muscles.
• They supply the skin of the anterior abdominal wall, the
muscles, and the parietal peritoneum.

59. SUB COSTAL NERVE
ILIOHYPOGASTRIC N.
ILIOINGUINAL N.
ANTERIOR SUPERIOR
ILIAC SPINE

60. DERMATOMES
The dermatome of
XIPHOID PROCESS
• T7 : in the epigastrium
over the xiphoid process,
• T10 : umbilicus UMBILICUS
• L1 : just above the
inguinal ligament and the
symphysis pubis.
PUBIC SYMPHYSIS

61. Anterior Abdominal Nerve Block
• Area of Anesthesia : The area of anesthesia is the skin of
the anterior abdominal wall.
• The nerves of the anterior and lateral abdominal walls
are the anterior rami of the 7th through the 12th
thoracic nerves and the first lumbar nerve (ilioinguinal
and iliohypogastric nerves).
• Indications : An anterior abdominal nerve block is
performed to repair lacerations of the anterior
abdominal wall.

62. BLOOD SUPPLY
• The skin near the midline is
supplied by branches of the
superior and the inferior
epigastric arteries.
• The skin of the flanks is
supplied by branches of the
intercostal, the lumbar, and the
deep circumflex iliac arteries
• the skin in the inguinal region
is supplied by the superficial
epigastric, the superficial
circumflex iliac, and the
superficial external pudendal
arteries, branches of the
femoral artery.

63. ARTERIES :
• The superior epigastric artery, one of the terminal branches of the
internal thoracic artery, enters the upper part of the rectus sheath
between the sternal and costal origins of the diaphragm.
• It descends behind the rectus muscle, supplying the upper central
part of the anterior abdominal wall, and anastomoses with the
inferior epigastric artery.
• The inferior epigastric artery is a branch of the external iliac artery
just above the inguinal ligament.
• It runs upward and medially along the medial side of the deep
inguinal ring . It pierces the fascia transversalis to enter the rectus
sheath anterior to the arcuate line .
• It ascends behind the rectus muscle, supplying the lower central part
of the anterior abdominal wall, and anastomoses with the superior
epigastric artery.
• Gives rise to the cremasteric artery , which accompanies the
spermatic cord.

64. • The deep circumflex iliac artery is a branch of the
external iliac artery just above the inguinal ligament.
• It runs upward and laterally toward the anterosuperior
iliac spine and then continues along the iliac crest.
• It supplies the lower lateral part of the abdominal wall.
• The lower two posterior intercostal arteries, branches of
the descending thoracic aorta, and the four lumbar
arteries, branches of the abdominal aorta, pass forward
between the muscle layers and supply the lateral part of
the abdominal wall

65. • Superficial epigastric arteries
Arise from the femoral artery and run superiorly toward the
umbilicus over the inguinal ligament.
• Anastomose with branches of the inferior epigastric artery.
• Superficial circumflex iliac artery
Arises from the femoral artery and runs laterally upward,
parallel to the inguinal ligament.
• Anastomoses with the deep circumflex iliac and lateral
femoral circumflex arteries.
• Superficial (external) pudendal arteries
Arise from the femoral artery, pierce the cribriform fascia,
and run medially to supply the skin above

66. VEINS
• Superficial Veins
• The superficial veins form a network
that radiates out from the umbilicus.
• Above, the network is drained into
the axillary vein via the lateral
thoracic vein.
• below, into the femoral vein via the
superficial epigastric and great
saphenous veins.
• A few small veins, the paraumbilical
veins, connect the network through
the umbilicus and along the
ligamentum teres to the portal vein.
This forms an important portal-
systemic venous anastomosis.

67. • Deep Veins
• The deep veins of the abdominal wall, the superior
epigastric, inferior epigastric, and deep circumflex iliac
veins, follow the arteries of the same name and drain
into the internal thoracic and external iliac veins.
• The posterior intercostal veins drain into the azygos
veins, and the lumbar veins drain into the inferior vena
cava.

68. Portal Vein Obstruction
• In cases of portal vein obstruction , the superficial veins
around the umbilicus and the paraumbilical veins become
grossly distended.
• The distended subcutaneous veins radiate out from the
umbilicus, producing in severe cases the clinical picture
referred to as caput medusae.
Caval Obstruction
• If the superior or inferior vena cava is obstructed, the venous
blood causes distention of the veins running from the
anterior chest wall to the thigh.
• The lateral thoracic vein anastomoses with the superficial
epigastric vein, a tributary of the great saphenous vein of the
leg.
• In these circumstances, a tortuous varicose vein may extend
from the axilla to the lower abdomen

69. Caput medusae

70. Lymphatic Drainage
• Lymphatics in the region above
the umbilicus
Drain into the axillary lymph nodes
which can be palpated just beneath
the lower border of the pectoralis
major muscle
• Lymphatics in the region below
the umbilicus
Drain into the superficial inguinal
nodes. Their efferent vessels primarily
enter the external iliac nodes and,
ultimately, the lumbar (aortic) nodes.
• The deep lymph vessels follow the
arteries and drain into the internal
thoracic, external iliac, posterior
mediastinal, and para-aortic (lumbar)
nodes.

71. Abdominothoracic Rhythm
• The abdominal muscles contract and relax with respiration,
and the abdominal wall conforms to the volume of the
abdominal viscera.
• There is an abdominothoracic rhythm. Normally, during
inspiration, when the sternum moves forward and the chest
expands, the anterior abdominal wall also moves forward.
• If, when the chest expands, the anterior abdominal wall
remains stationary or contracts inward, it is highly probable
that the parietal peritoneum is inflamed and has caused a
reflex contraction of the abdominal muscles.

72. Visceroptosis
• The shape of the anterior abdominal wall depends on the
tone of its muscles.
• A middle-aged woman with poor abdominal muscles who
has had multiple pregnancies is often incapable of
supporting her abdominal viscera.
• The lower part of the anterior abdominal wall protrudes
forward, a condition known as visceroptosis.
• This should not be confused with an abdominal tumor such
as an ovarian cyst or with the excessive accumulation of fat
in the fatty layer of the superficial fascia.

73. Inguinal Canal
• The inguinal canal is an oblique passage through the lower part
of the anterior abdominal wall.
• In the males, it allows structures to pass to and from the testis
to the abdomen.
• In females it allows the round ligament of the uterus to pass
from the uterus to the labium majus.
• The canal is about 1.5 in. (4 cm) long in the adult and extends
from the deep inguinal ring , downward and medially to the
superficial inguinal ring.
• It lies parallel to and immediately above the inguinal ligament.
• In the newborn child, the deep ring lies almost directly
posterior to the superficial ring so that the canal is considerably
shorter at this age.
• Later, as the result of growth, the deep ring moves laterally.

74. • The deep inguinal ring is an oval opening in the fascia
transversalis, lies about 0.5 in. (1.3 cm) above the inguinal
ligament midway between the anterior superior iliac spine
and the symphysis pubis.
• Related to it medially are the inferior epigastric vessels.
• The margins of the ring give attachment to the internal
spermatic fascia (or the internal covering of the round
ligament of the uterus).
• The superficial inguinal ring is a triangular-shaped defect in
the aponeurosis of the external oblique muscle and lies
immediately above and medial to the pubic tubercle.
• The margins of the ring, sometimes called the crura, give
attachment to the external spermatic fascia.

75. Parts of external and internal oblique muscles
removed

76. Walls of the Inguinal Canal
• Anterior wall: Skin,Superficial fascia External oblique aponeurosis
and fleshy fibre of Internal oblique laterally. This wall is therefore
strongest where it lies opposite the weakest part of the posterior
wall, namely, the deep inguinal ring.
• Posterior wall: Conjoint tendon medially, fascia transversalis
laterally. This wall is therefore strongest where it lies opposite the
weakest part of the anterior wall, namely, the superficial inguinal
ring.
• Roof or superior wall: Arching lowest fibers of the internal oblique
and transversus abdominis muscles.
• Floor or inferior wall: Upturned lower edge of the inguinal
ligament and, at its medial end, the lacunar ligament

77. Inguinal canal showing the arrangement of
the external oblique muscle (A), the internal
oblique muscle (B), the transversus muscle
(C), and the fascia transversalis (D)

78. Deep structures of the inguinal canal. The
aponeurosis of external oblique has been
removed

79. Function of the Inguinal Canal
• The inguinal canal allows structures of the spermatic
cord to pass to and from the testis to the abdomen in the
male. (Normal spermatogenesis takes place only if the
testis leaves the abdominal cavity to enter a cooler
environment in the scrotum.)
• In the female, the smaller canal permits the passage of
the round ligament of the uterus from the uterus to the
labium majus.

80. Mechanics of the Inguinal Canal
• The inguinal canal in the lower part of the anterior
abdominal wall is a site of potential weakness in both sexes.
• Except in the newborn infant, the canal is an oblique
passage with the weakest areas, namely, the superficial and
deep rings, lying some distance apart.
• The anterior wall of the canal is reinforced by the fibers of
the internal oblique muscle immediately in front of the
deep ring.
• The posterior wall of the canal is reinforced by the strong
conjoint tendon immediately behind the superficial ring.

81. • On coughing and straining, as in micturition, defecation,
and parturition, the arching lowest fibers of the internal
oblique and transversus abdominis muscles contract,
flattening out the arched roof so that it is lowered toward
the floor. The roof may actually compress the contents of
the canal against the floor so that the canal is virtually
closed.
• When great straining efforts may be necessary, as in
defecation and parturition, the person naturally tends to
assume the squatting position; the hip joints are flexed,
and the anterior surfaces of the thighs are brought up
against the anterior abdominal wall. By this means, the
lower part of the anterior abdominal wall is protected by
the thighs

82. Action of the muscles on the inguinal canal.
the canal is obliterated• when the muscles
contract