anterior abdominal wal

1. Introduction and overview of the
Abdominal
Dr. Amaan
8th August/ Monday

2. NINE REGIONS OF ABDOMEN

3. Abdomen is divided into 9 regions by 4 imaginary planes:
2 horizontal & 2 vertical
1. Transpyloric plane of Addison: midway between the supra sternal
notch & the pubic symphysis (roughly a hands breadth below the
xiphisternal joint)
• Anteriorly: passes through the tip of 9th coastal cartilage
• Posteriorly: lower border of body of L1
2. Transtubular plane:
• Anteriorly: passes through the tubercles of iliac crest
• Posteriorly: upper border of body of L5

4. Right and left lateral/ Vertical lines (Midclavicular Plane):
•Above: midpoint of the clavicle
•Below: mid inguinal point (mid point between the ASIS –
pubic symphysis)

7. The abdomen is the lower part of the
trunk, below the diaphragm
The abdominal cavity is subdivided by
the plane of the pelvic inlet into
• Large upper abdominal cavity
proper
• Small lower pelvic cavity

8. Abdominal cavity boundary:
Superiorly: diaphragm
Inferiorly: continues with the pelvic cavity at pelvic inlet
Anteriorly: anterior abdominal wall, formed by muscles
Posteriorly: posterior abdominal wall, formed by lumbar vertebrae
and muscles
Laterally: lower ribs and parts of muscles the anterior abdominal
wall

9. Pelvic cavity boundary:
Superiorly: continuous with the
abdominal cavity at the pelvic inlet
Inferiorly: pelvic diaphragm
Posteriorly: sacrum and coccyx
Anteriorly: pubic bones
Laterally: hip bones
Contents:
Loops of small intestine, sigmoid colon, rectum, anus, urinary
bladder, urethra, prostate, vas deferns, uterus, ovaries, vagina

10. Perinium
The perineum is an area outlined by
the diamond shaped pelvic outlet.
Boundaries:
Anteriorly: pubic symphysis
Posteriorly: coccyx
Laterally: ischiopubic rami &
sacrotuberous ligament
Roof: pelvic diaphragm
Floor: skin
Content: external genitalia(penis &scrotum in male and vulva in female)& anus

11. SKIN AND SUPERFICIAL FASCIA
The Skin
Capable of undergoing enormous stretching as seen in
• pregnancy;
• accumulation of fat, obesity
• accumulation of fluid called ascites,

12. The Umbilicus
It is the normal scar in the anterior abdominal wall formed by the
remnants of the root of the umbilical cord. L3 – L4 level
Anatomical Importance
1. With reference to the lymphatic and venous drainage, the level of the
umbilicus is a watershed.
2. The skin around the umbilicus is supplied by segment T10 of the
spinal cord.
3. The umbilicus is one of the important sites at which tributaries of the
portal vein anastomose with systemic veins (portocaval
anastomoses).

13. The subcutaneous venous circulation in: (a) Normal subjects, (b) portal
obstruction showing caput medusae, (c) superior vena caval obstruction, and
(d) inferior vena caval obstruction (arrows indicate the direction of blood flow)

14. Embryological Importance
1. Umbilicus is the meeting point of
4 folds of embryonic plate.
2. This is also the meeting point of
three systems
• digestive (vitellointestinal duct),
• excretory (urachus), and
• vascular (umbilical vessels).

15. Congenital anomalies:
Of umbilicus are fistulae and
exomphalos (omphalocele)
a) Fecal fistula: failure of vitello
intestinal duct to obliterate
b) Urinary fistula: failure to uracus to
obliterate
c) Omphalocele: failure of midgut loop
to return in the abdominal cavity

16. SUPERFICIAL FASCIA
1. Below the level of the umbilicus, the superficial fascia of the anterior
abdominal wall is divided into:
a. Superficial fatty layer (fascia of Camper) and
b. Deep membranous layer (fascia of Scarpa)
• The fatty layer is continuous with the superficial fascia of the
adjoining part of the body.
• The membranous layer is continuous below with a similar
membranous layer of superficial fascia of the perineum known as
Colles’ fascia.

17. 2. In the median plane, the membranous layer is thickened to form the
suspensory ligament and fundiform ligament of the penis or clitoris.
3. The fascia contains:
a. Variable quantity of fat
b. Cutaneous nerves.
c. Cutaneous vessels.
d. Superficial lymphatics.
Cutaneous Nerves
The skin of the anterior abdominal wall is supplied by
• The lower six thoracic nerves (lower five intercostal and subcostal)
and by the first lumbar nerve.

18. The cutaneous nerves of the anterior abdominal wall

19. Cutaneous Arteries
1. Anterior cutaneous arteries
2. Lateral cutaneous arteries
3. Superficial inguinal arteries supply the skin of the lower part of the
abdomen. These are:
• Superficial epigastric artery
• Superficial external pudendal artery
• Superficial circumflex iliac artery
Cutaneous Veins
The veins accompany the arteries.
The superficial inguinal veins drain into the great saphenous vein.

20. Arteries of the anterior abdominal wall

21. Superficial Lymphatics
Above the level of the umbilicus the lymphatics run upwards to drain
into the axillary lymph nodes.
Below the level of the umbilicus they run downwards to drain into the
superficial inguinal lymph nodes.

22. Superficial lymphatics of the anterior abdominal wall

23. Disorders of the abdomen:
1. Hernia: it is the protrusion of an organ through the wall
(inguinal hernia, femoral)
2. Abdominal pain
• Upper abdominal pain: due to involvement of gall bladder,
stomach, duodenum & pancreas
• Central: due to involvement of small bowel & kidneys
• Lower: urinary bladder, uterus, cecum & sigmoid colon
3. Abdominal mass: hepatomegaly, splenomegaly, carcinoma
of stomach, accumulation of feces in bowel

24. 4. Abdominal distension: six common causes
i. Fetus
ii. Flatus
iii. Feces
iv. Fat
v. Fluid (ascites)
vi. Fibroids