The document describes the anatomy of the anterior abdominal wall. It is divided into nine quadrants and contains skin, superficial fascia with fatty and membranous layers, deep fascia, three muscle layers (external oblique, internal oblique, transversus abdominis), rectus abdominis muscles, pyramidalis muscle, extraperitoneal fascia, and parietal peritoneum from external to internal. Key nerves are branches of thoracic and lumbar nerves, and arteries include the superior and inferior epigastric arteries. Lymphatic drainage is to axillary nodes above the umbilicus and inguinal nodes below.

1. ANTERIOR ABDOMINAL WALL

2. The abdomen is the region of the body that is located between the diaphragm above and the pelvic inlet
below.
It is divided into nine quadrants, by:
Two vertical lines at the level of:
 Midclavicular point superiorly
 Midinguinal point inferiorly
Two horizontal lines at the level of:
 Subcostal edges superiorly
 Right and left iliac tubercles inferiorly

4. The structures of the abdominal wall from out side to inside.
1. Skin.
2. Superficial fascia.
3. Deep fascia
4. Muscles.
5. Extraperitoneal fascia
6. Parietal peritoneum.

5. SKIN
Skin is loosely attached to the underlining structures except the umbilicus.
The umbilicus is a scar representing the site of attachment of the umbilical cord in the fetus; it is situated in
the linea alba.

6. SUPERFICIAL FASCIA
The superficial fascia is divided into:
 Superficial fatty layer (fascia of Camper)
 Deep membranous layer (Scarpa's fascia)
SUPERFICIAL FATTY LAYER (CAMPER’S FASCIA).
It’s continuous with superficial fat over the rest of the body.
In the scrotum is modified as a thin smooth muscular layer called dartos muscle.

7. Deep membranous layer.(Scarpa’s fascia).
 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.

9. DEEP FASCIA
Is a thin layer of connective tissue covering the muscles, it lies immediately deep to the membranous layer
of superficial fascia.

10. MUSCLES
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

11. 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.

12. ORIGIN
Lower eight ribs
(5-12)
INSERTION
NERVE SUPPLY
lower six
thoracic nerves
(T7-T12)
iliohypogastric
and ilioinguinal
nerves (L1)
ACTION
Supports abdominal contents;
compresses abdominal
contents
assists in flexing and rotation
of trunk
assists in forced expiration,
micturition, defecation,
parturition, and vomiting
Xiphoid process
linea alba
pubic crest
pubic tubercle
iliac crest
EXTERNAL OBLIQUE MUSCLE
Broad, thin, muscular sheet.

13. There is a triangular-shaped defect in the external oblique aponeurosis that lies immediately above and
medial to the pubic tubercle known as superficial inguinal ring
The spermatic cord (or round ligament of the uterus) passes through this opening and carries the external
spermatic fascia (or the external covering of the round ligament of the uterus) from the margins of the ring

14. 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 .

15. From the medial end of the ligament, the lacunar
ligament extends backward and upward to the
pectineal line on the superior ramus of the pubis

16. ORIGIN
Lumbar fascia,
iliac crest,
lateral two thirds
of the inguinal
ligament.
INSERTION
NERVE SUPPLY
lower six
thoracic nerves
(T7-T12)
iliohypogastric
and ilioinguinal
nerves (L1)
ACTION
Supports abdominal contents;
compresses abdominal
contents
assists in flexing and rotation
of trunk
assists inforced expiration,
micturition, defecation,
parturition, and vomiting
lower three ribs
and their costal
cartilages
xiphoid process.
linea alba.
symphysis
pubis.
INTERNAL OBLIQUE MUSCLE
The internal oblique muscle is also a broad, thin, muscular sheet that lies deep to the external oblique

17. Lower fibres of internal oblique are joined
by similar fibers from the transversus
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 .

18. TRANSVERSUS MUSCLE
Thin sheet of muscle that lies deep to the internal oblique
ORIGIN
Lower six costal
cartilages
Lumbar fascia,
iliac crest,
lateral two thirds
of the inguinal
ligament.
INSERTION
NERVE SUPPLY
lower six
thoracic nerves
(T7-T12)
iliohypogastric
and ilioinguinal
nerves (L1)
ACTION
compresses abdominal
contents
xiphoid process.
linea alba.
Symphysis
pubis.

19. 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.

20. ORIGIN
symphysis
pubis
pubic crest.
INSERTION
NERVE SUPPLY
lower six
thoracic nerves
(T7-T12)
ACTION
compresses abdominal
contents; flexes vertebral
column; accessory muscle of
expiration
fifth, sixth, and
seventh costal
cartilages
xiphoid process
RECTUS ABDOMINIS

21. 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.
The rectus abdominis muscle is divided into distinct segments by three transverse tendinous intersections at
the level of:
 xiphoid process.
 umbilicus.
 halfway between these two.

22. PYRAMIDALIS
ORIGIN
anterior surface
of the pubis.
INSERTION
NERVE SUPPLY
Twelvth thoracic
nerve
T12
ACTION
Tenses the linea alba
Linea alba

23. EXTRAPERITONEAL FASCIA
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
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.

24. NERVE SUPPLY
 The nerves of the anterior abdominal wall are the anterior rami of the lower six thoracic and the first
lumbar nerves.
 The thoracic nerves are the lower five intercostal nerves and the subcostal nerves
 First lumbar nerve is represented by the iliohypogastric and ilioinguinal nerves, branches of the lumbar
plexus
They supply the skin of the anterior abdominal wall, the muscles, and the parietal peritoneum.
 The lower six thoracic nerves pierce the posterior wall of the rectus sheath to supply the rectus muscle
and the pyramidalis (T12 only).

25.  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.
 Dermatomes of the abdominal wall.
 The xiphoid process: T7
 The umbilicus: T10
 The pubis: L1

26. 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 arteries
 Lumbar arteries
 Deep circumflex iliac arteries

27. The superior epigastric artery, one of the terminal branches of the internal thoracic artery, enters the
upper part of the rectus sheath
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.
the rectus muscle, supplying the lower central part of the anterior abdominal wall, and anastomoses with the
superior epigastric artery.
The deep circumflex iliac artery is a branch of the external iliac artery just above the inguinal ligament.
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

28. VENOUS DRAINAGE
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.
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.

29.  superficial
 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
 The deep lymph vessels follow the arteries and drain into the internal thoracic, external iliac, posterior
mediastinal, and para-aortic (lumbar) nodes.