2. STRUCTURE
MADE UP OF:
1. Skin
2. Superficial fascia
3. Deep fascia
4. Muscles
5. Extraperitoneal fascia
6. Parietal peritoneum
3. SKIN
• Skin is loosely attached to the underlying
structures except at the umbilicus, where it is
tethered to the scar tissue.
• The umbilicus is a scar representing the site of
attachment of the umbilical cord in the fetus, it
is situated in linea alba.
DERMATOME:
• The cutaneous nerve supply is derived from
the anterior rami of the lower six thoracic and
the first lumbar nerves.
• The dermatome of T7 is located over the
xiphoid process
• The dermatome of T10 includes the umbilicus
• That of L1 lies just above the inguinal ligament
and the symphysis pubis.
4. SUPERFICIAL FASCIA
• THE SUPERFICIAL FASCIA IS DIVIDED INTO:
– Superficial fatty layer (Camper’s fascia)
– Deep membranous layer (Scarpa’s fascia)
• The FATTY LAYER is continuous with the superficial
fat over the rest of the body and may be extremely
thick (8cm) or more in obese 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.
DEEP FASCIA
• It lies immediately deep to the membranous
layer of superficial fascia
5. MUSCLES
• The muscles of anterior abdominal wall consists of
three broad thin sheets.
FROM EXTERIOR TO INTERIOR THEY ARE:
• External oblique
• Internal oblique
• Transversus abdominis
• On either side of the midline anteriorly is, in
addition, a wide vertical muscle, the RECTUS
ABDOMINUS.
• 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 might contain
a small muscle called the PYRAMIDALIS.
6. A. EXTERNAL OBLIQUE
• ORIGIN: The outer surfaces of the lower eight ribs and
fans out to be,
• INSERTION: The xiphoid process, the linea alba, the
pubic crest, the pubic tubercle, and the anterior half of
the iliac crest.
• Most of the fibers are inserted by means of a broad
aponeurosis
• A triangle 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.
7. B. INTERNAL OBLIQUE
• ORIGIN:
Lumbar fascia, the anterior two thirds of the iliac
crest, and the lateral two thirds of the inguinal
ligament.
• INSERTION:
The lower borders of the lower three ribs, and
their costal cartilages, the xiphoid process, the
linea alba, and the symphysis pubis.
8. • EXTERNAL OBLIQUE MUSCLE FIBERS move downwards and
medially.
• INTERNAL OBLIQUE MUSCLE FIBERS move upwards and medially.
9. C. TRANSVERSUS ABDOMINUS
• ORIGIN:
The deep surface of the lower six costal
cartilages, the lumbar fascia, the anterior two
thirds of the iliac crest, and the lateral third of
the inguinal ligament.
• INSERTION:
The xiphoid process, the linea alba, and the
symphysis pubis.
10. D. RECTUS ABDOMINIS
• The rectus abdominis is a long strap
muscle that extends along the whole
length of the anterior abdominal wall.
• It is broaded above and lies close to the
midline, being separated from its fellow
by the linea alba.
• ORIGIN: pubic crest
• INSERTION: ribs (5th, 6th, 7th), xiphoid
process.
11. • The rectus abdominis muscle is
divided into distinct segments by
three transverse tendinous
intersections:
• 1. one at the level of xiphoid process
• 2. one at the level of the umbilicus
• 3. one halfway between these two
• These insertions are strongly attached
to the anterior wall of the rectus
sheath.
12. E. PYRAMIDALIS
• The pyramidalis muscle is often absent.
• ORIGIN: anterior surface of the pubis
• INSERTION: linea alba
• It lies infront of the lower part of the
rectus abdominis.
13. RECTUS SHEATH
• The rectus sheath is a long fibrous sheath
that encloses the rectus abdominis muscle
and pyramidalis muscle (if present)
• It is formed mainly by the aponeuroses of
the three lateral abdominal muscles.
• 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.
14. FUNCTIONS OF MUSCLES OF
ANTERIOR ABDOMINAL WALL
• OBLIQUE MUSCLE: laterally flex and route the trunk
• RECTUS ABDOMINIS: flexes the trunk and stabilizes the pelvis
• PYRAMIDALIS: keeps the linea alba taut during the process.
• The muscles of the anterior and lateral abdominal walls assist the diaphragm during
inspiration by relaxing as the diaphragm descends so that the abdominal viscera can
be accommodated.
• The muscles assist in the act of forces expiration that occurs during coughing and
sneezing by pulling down the ribs and sternum.
• Their tone plays an important part in supporting and protecting the abdominal viscera.
15. • By contracting simultaneously with the diaphragm, with the glottis of the
larynx closed, they increase the intra abdominal pressure and help in:
1. Micturation
2. Defecation
3. Vomiting
4. Parturition
16. NERVE SUPPLY OF MUSCLES OF
ANTERIOR ABDOMINAL WALL
• The oblique and transversus
abdominis muscles are supplied by
the lower six thoracic nerves and the
iliohypogastric and ilioinguinal nerves
(L1).
• The rectus muscle is supplied by the
lower six thoracic nerves.
• The pyramidalis is supplied by the 12th
thoracic nerve.
17. • FASCIA TRANSVERSALIS
• The fascia transversalis is a thin layer of fascia that lines the transversus
abdominis muscle.
• EXTRAPERITONEAL FAT:
• The extraperitoneal fat is a thin layer of connective tissue that contains a variable
amount of fat and lies between the fascia tranversalis and the parietal
peritoneum.
• PARIETAL PERITONEUM:
• The walls of abdomen are lined with parietal peritoneum
• This is a thin serous membrane and is continuous below with the parietal
peritoneum lining the pelvis.
18. BLOOD SUPPLY OF
ANTERIOR ABDOMINAL WALL
• ARTERIAL SUPPLY:
– Superior Epigastric artery: branch of Internal
Mammary artery.
– Inferior Epigastric artery: branch of External
Iliac artery
– Two Posterior Intercostal art.: Desc. Thor.
Aorta
– Four Lumbar arteries: Desc. Thor. Aorta
– Deep Circumflex iliac artery: branch of Ext.
Iliac artery
• VEINS:
• Above the umbilicus mainly into the axillary
vein via the lateral thoracic vein.
• Below the umbilicus into the femoral vein
through the superficial epigastric and the
great saphenous veins.
19. NERVE SUPPLY OF
ANTERIOR ABDOMINAL WALL
• Anterior rami of Lower 6 thoracic nerves
– T7 – T11 intercostal nerves
– T12: Subcostal nerve
• Anterior ramus of the 1st lumbar nerve
– Ilioinguinal nerve
– Iliohypogastric nerve
• Pass forward between the internal oblique
and transversus abdominis muscle.
20. LYMPH DRAINAGE OF
ANTERIOR ABDOMINAL WALL
SUPERFICIAL LYMPH VESSELS:
• Above umbilicus: anterior group of axillary
nodes
• Below umbilicus: superficial inguinal lymph
nodes
DEEP YMPH VESSELS:
Drain into the:
Internal thoracic, external iliac, posterior
mediastinal and para aortic (lumbar) nodes.
21. MULTIPLE CHOICE QUESTIONS
1. SUPERIOR EPIGASTRIC ARTERY IS A BRANCH OF:
• A. Descending thoracic aorta
• B. Abdominal aorta
• C. Internal thoracic artery
• D. External iliac artery
22. 2. MUSCLE FIBERS OF THE EXTERNAL OBLIQUE MOVE IN WHICH DIRECTION:
• A. upwards and medially
• B. upwards and laterally
• C. downwards and laterally
• D. downwards and medially
23. 3. INSERTION OF RECTUS ABDOMINIS:
• A. linea alba
• B. pubic crest
• C. xyphoid process
• D. anterosuperior iliac spine
