The document summarizes the anatomy of the abdominal wall and abdominal viscera. It describes the layers of the abdominal wall from the skin to the peritoneum. It details the five anterolateral muscles - external oblique, internal oblique, transversus abdominis, rectus abdominis, and pyramidalis. It also discusses the innervation, blood supply, and lymphatic drainage of the abdominal wall. Finally, it summarizes the peritoneal folds including the omenta, mesenteries, and ligaments that support the abdominal organs.

1. Abdomen Part 1
Themba Hospital FCOG(SA) Part 1 Tutorials
By Dr N.E Manana

2. Organization pattern
• Fig 4.23

4. Abdominal wall
• The abdominal wall covers a large area
• Its layers consist of the:
1. Skin
2. Superficial fascia (subcutaneous tissue)
3. Muscles
4. Deep fascia
5. Extraperitoneal fascia and
6. Peritoneum
• Superficial fascia is a layer of fatty connective tissue, usually a single layer
except in the lower region of the anterior abdominal wall, where it divides
into a fatty layer and a membranous layer

5. • Fig 4.24

6. • Fig 4.25

7. Anterolateral muscles
• The are 5 muscles in this group, 3 flat and 2 vertical
• Each muscle has a specific function but together the maintain many normal
physiologic functions (respiration, coughing , vomiting, labour, urination
and defecation)
Flat muscles:
• 1. External oblique (EOM) is the most superficial, immediately deep to the
superficial fascia, moves inferomedial and its aponeuroses forms the linea
alba anterior
• Associated tendons: Inguinal ligament(Lower border, from the ASIS to the
pubic tubercle), lacunar ligament(medial end on the inguinal ligament, into
the pecten pubis), cooper’s ligament

8. • Fig 4.27

9. • Fig 4.28 and 4.29

10. Anterolateral muscles
Flat muscles:
2. Internal oblique muscle(IOM): Deeper to the EOM, smaller and thinner,
passing superomedial, anteriorly has aponeuroses that blends into the linea
alba
3. Transversus abdominis (TAM) : Deep to the IOM, direction of most fibers
are transverse, its aponeuroses blends into the linea alba
• Each of the muscles is covered on its anterior and posterior surface by a
layer of abdominal fascia, this layers are unremarkable except for the layer
deep to the TAM (Tranversalis fascia)
• The fascia lines the abdominal and pelvic cavity, in the pelvis it is known as
the parietal pelvic fascia

11. • 4.30 and 4.31

13. Vertical muscles
• The 2 vertical muscles are the large 1. Rectus abdominis and 2. The
pyramidalis
1. The rectus abdominis is a long, paired (separated by the linea alba) ,
flat muscle that extends the length of the abdominal wall, widening
and thinning
• In its length it is intersected by thin transverse fibrous bands
(tendinous intersections)
2. Pyramidalis , its small, triangular, has its base at the pubis and its
apex attached to the linea alba

14. • 4.32

15. Rectus sheath
• 4.33

16. • 4.34

17. Innervation
• The anterolateral abdominal wall is supplied by T7-T12 and L1 spinal
nerves
• The anterior rami of these nerves passes in an inferior medial
direction
• They give off a lateral cutaneous branch as they proceed, and end up
as the anterior cutaneous branch
• T7-T11 leave their intercostal spaces , deep into the costal cartilage
and continue between the IOM and the TAM
• Branches of L1 are ilio-hypogastric nerve and ilio-inguinal nerve

18. • 4.36 and 4.37

20. Arterial supply and venous drainage
Superficially
• The superior part of the wall is supplied by the musculophrenic artery, a
terminal branch of the internal thoracic artery
• The inferior part is supplied by the superficial epigastric artery(Medial) and
the superficial circumflex iliac artery (lateral) branches of the femoral
artery
Deeper
• Superior: superior epigastric artery, lateral part by branches of the 10th and
11th intercostal arteries
• Inferior: inferior epigastric artery (medial), deep circumflex iliac
artery(lateral) , both branches of the external iliac artery

21. • 4.39

22. • 4.40

23. Abdominal viscera
• A thin membrane lines the walls of the abdominal cavity and covers
much the viscera (Peritoneum: Parietal and visceral)
• Some organs are suspended in the cavity (intraperitoneal) by folds
(mesenteries) others are outside (retroperitoneal)
• The peritoneal cavity is subdivided into the greater sac and lesser
sac(omental bursa),
• They are continuous via the omental foramen which is surrounding by
the portal vein, hepatic artery proper and bile duct anteriorly, IVC
posteriorly, caudate lobe of the liver superiorly and 1st part of
duodenum inferiorly

24. • 4.53

25. • 4.54

26. Peritoneal folds
• 1. Omenta, 2. Mesentery and 3. Ligaments
1. Omenta
• Consists of two layers of peritoneum, which pass from the stomach and the
1st part of the duodenum to other viscera
• They are two: (A) Greater omentum from dorsal mesentery, (B) Lesser
omentum from the ventral mesentery
(A) Greater omentum is large, apron like , attaches to the greater curvature
of the stomach and the 1st part of the duodenum
• It ascends to be associated with the peritoneum on the transverse colon
and its mesocolon before arriving at the posterior abdominal wall

27. Peritoneal folds
(B) Lesser omentum
• 2 layered peritoneal, extends from the lesser curvature of the
stomach and the 1st part of the duodenum to the inferior surface of
the liver
• It is divided into (I) a medial hepatogastric ligament and (II) a lateral
hepatoduodenal ligament
• The hepatoduodenal serves as the anterior boarder of the omental
foramen
• Supplied by the right and left gastric vessels

28. • 4.56

30. • 4.60

31. Peritoneal folds
2. Mesenteries
• Attach visceral to the posterior abdominal wall, they allow movement and
provide vessels
• Include: Part of small intestine “mesentery”, transverse mesocolon,
sigmoid mesocolon
• Mesentery: It’s large , fan shaped, double layered fold, connects the
jejunum and ileum to the posterior abdominal wall, superior part is at the
duodenojejunal junction
• Transverse mesocolon: connects the transverse colon to the posterior
abdominal wall across the anterior surface of the pancreases
• Sigmoid mesocolon: inverted, v-shaped , the sigmoid and superior rectal
vessels pass via it, along with accompanying nerves and lymphatics

32. • 4.61

33. Peritoneal folds
3. Ligaments
• Two layers of peritoneum that connects two organs to each other or
an organ to the body wall
• They are usually named after the structures being connected
• Such as the splenorenal or the gastrophrenic ligament

34. Thank you