2. OBJECTIVES
• TO EXPLORE ABDOMINAL WALL MUSCULATURE
• TO EXPLORE THE CONCEPT OF REFERRED PAIN
• DESCRIBE THE STRUCTURE AND LAYERS OF THE ABDOMINAL
WALL
• DESCRIBE THE MAJOR LANDMARKS OF THE ABDOMINAL WALL
• DESCRIBE COMMONLY USED SURGICAL INCISIONS IN THE
ABDOMINAL WALL
• DESCRIBE AND GIVE EXAMPLES OF REFERRED PAIN RELATING
TO THE ABDOMINAL CAVITY
3. ABDOMINAL WALL
ABDOMINAL WALL IS SUBDIVIDED INTO THE ANTERIOR WALL, RIGHT AND LEFT LATERAL
WALLS AND THE POSTERIOR WALL. THE BOUNDARY BETWEEN THE ANTERIOR AND THE
LATERAL WALLS IS INDEFINITE; THE TERM ANTEROLATERAL ABDOMINAL WALL IS USED.
LANDMARKS OF THE ABDOMINAL WALL
UMBILICUS : OBVIOUS FEATURE OF THE ANTEROLATERAL ABDOMINAL WALL AT SPINAL
LEVEL L3
EPIGASTRIC FOSSA (PIT OF THE STOMACH):
SLIGHT DEPRESSION IN THE EPIGASTRIC REGION, JUST INFERIOR TO THE XIPHOID PROCESS.
PARTICULARLY NOTICEABLE WHEN A PERSON IS IN THE SUPINE POSITION BECAUSE THE
ABDOMINAL ORGANS SPREAD OUT. HEARTBURN IS COMMONLY FELT AT THIS SITE.
4. Linea Alba
Aponeuroses of abdominal muscles, separating the left and
right rectus abdominis. Visible in lean individuals because of the
vertical skin groove superficial to it. If the linea alba is lax, when
the rectus abdominis contract the muscles spread apart. This is
called divarication of recti.
Pubic Crest and Symphysis
The upper margins of the pubic bones and the cartilaginous joint
that unite them. Can be felt at the inferior end of the linea alba.
5. Inguinal Groove
A skin crease that is parallel and just inferior to the inguinal ligament (runs
between ASIS and pubic tubercle). Marks the division between the abdominalwall
and the thigh.
Semilunar lines
Slightly curved,Tendinous line on either side of the rectus abdominis.
Tendinous Intersections of Rectus Abdominis
Clearly visible in persons with well-developed rectus muscles.The interdigitating
bellies of the serratus anterior and external oblique muscles are also visible.
Arcuate Line (aka Douglas’line)
Where the fibrous sheath stops (inferior limit of the posterior layer of the rectus
sheath). 1/3 of the way from the umbilicus to the pubic crest.
6. • the anterolateral abdominal wall is bounded superiorly by the cartilages of
the 7th-10th ribs, and the xiphoid process of the sternum, and inferiorly by
the inguinal ligament and the superior margins of the anterolateral aspects of
the pelvic girdle (iliac crests, pubic crests and pubic symphysis).
• the anterolateral abdominal wall consists of skin, subcutaneous tissue
(superficial fascia/fat), muscles and their aponeuroses, deep fascia,
extraperitoneal fat and parietal peritoneum.
7. ANTEROLATERAL ABDOMINAL WALL LAYERS
• skin, superficial fascia (subcutaneous tissue): a superficial
fatty layer (camper’s fascia) and a deeper membranous layer
(scarpa’s fascia)
• investing fascia: tissue that covers the muscle layers
• abdominal muscles: three flat layers,
• endoabdominal fascia: transversalis fascia,
• extraperitoneal fat: connective tissue that is variable in
thickness
• peritoneum.
• muscles of the abdominal wall are of considerable practical
importance because their anatomy forms the basis of
abdominal incisions .
• inguinal region of great clinical importance in management
of hernia.
8. THE ANTEROLATERAL ABDOMINAL WALL
• there are five (bilaterally paired)
muscles in the anterolateral
abdominal wall, three flat muscles
and two vertical muscles.
• flat muscles – external oblique,
internal oblique and transversus
abdominis
• vertical muscles – rectus abdominis
and pyramida
9. obliques running diagonally and perpendicularto each other, and the fibres
of the transversus running transversely.
10. Muscle Origin Insertion
External
Oblique
External surfaces of the 5th to 12th ribs Linea alba, pubic tubercle
and anterior half of iliac
crest
Internal
Oblique
Thoracolumbarfascia,anterior two
thirds of iliac crest and connective
tissue deep to lateral third of inguinal
ligament
Inferior borders of the 10th to
12th ribs, linea alba and
pectin pubis via conjoint
tendon
Transversus
Abdominis
Internal surfaces of 7th to 12th costal
cartilages, thoracolumbarfascia, iliac
crest and connective tissue deep to
lateral third of inguinal ligament
Linea alba with
aponeurosesof internal
oblique, pubic crest, and
pectin pubis via conjoint
tendon
11. ABDOMINAL WALL
• each rectus enclosed in a sheath
(rs) formed by the aponeuroses of
the anterolateral muscles
rectus sheaths fuse in the midline to
form the linea alba (white line) –
almost an avascular line along which
the abdomen can be opened rapidly
12. LATERAL ABDOMINAL MUSCLES – ANATOMY &
CLINICAL IMPORTANCE
• make up the rectus sheath
• form the inguinal canal
• must be divided in making
lateral abdominalincisions
13. FUNCTIONOF ANTEROLATERALABDOMINAL
MUSCLES.
• PROTECTION OF THE VISCERA FROM INJURY
• MAINTAIN THE POSITION OF THE VISCERAIN THE ERECT POSTURE
AGAINST THE ACTION OF GRAVITY
• ASSIST IN BOTH QUIET AND FORCED EXPIRATION,IN COUGHING AND
VOMITING.
• INVOLVED IN ANY ACTION THAT INCREASES INTRA-ABDOMINAL
PRESSURE,INCLUDING PARTURITION,MICTURITION &DEFECATION
14. NEUROVASCULAR SUPPLY TO THE ABDOMINAL
MUSCLES & SKIN
• (segmentalns (t7 – t12 & l1 ·
• nerves supply to the skin segmentaland
the same nerve supply the parietal
peritoneum
important segmentalmidline dermatomes
T8 (epigastrium),
T10 (umbilical),
T12 (suprapubic)
L1 (groin & scrotum)
blood supply – superior &
• inferior epigastric vessels
•
15. LOCATION OF COMMON ABDOMINAL INCISIONS
• to gain best access to the abdominal
cavity
• allows adequate exposure
• avoidance of damage to nerves
• prevention of injury to muscles &
fasciae
• quick healing &minimum scarring
• best cosmetic effect
16. ABDOMINAL SURGICAL INCISIONS
• location depends on the type of operation,
location of organs, bony & cartilaginous
boundaries,avoidance of(esp.
motor)nerves, maintenance ofblood supply,
prevention of injury to muscles & fascia
• transecting muscles causes necrosis of
muscle fibres; thus muscle are split between
their fibres.
• muscles and viscera are retracted towards
their neurovascularsupply
• muscle heal by scar , become weak and may
develop hernia
17. INTERNAL SURFACE OF ANTEROLATERAL
ABDOMINAL WALL
• covered by parietal perioteum
• supplied by blood vessels of the abdominopelvic
wall
• innervated by somatic nerves
• inflammation of the peritoneum (peritonitis) causes
pain in the overlying skin & increases the tone of
anterolateral abdominal muscles
• a patient with acute abdomen(intense abd.
pain)would have spasms of abdominal muscles
(guarding); muscular rigidity that cannot be will fully
suppressed
• injury to peritoneum(e.g. stab wounds) may lead to
peritonitis
18. ABDOMINAL SURGICAL INCISIONS
• damage of motor nerves will lead to
paralysis of muscle fibres supplied
by the nerves,leading to weakening
of abd. wall
• if muscle or aponeurotic layers do
not heal properly, a hernia mayoccur
through the defect
• incisional hernia – protrusionof a fold
of the peritoneum contained
omentum or an organ through the
surgical incision or scar
19. SURGICAL INCISION
midline incision
surgeons suture the linea alba
together to provide a strong closure
transverse incision
surgeons suture the external oblique
aponeurosestogetherto provide a strong
closure
20. APPENDICECTOMY
• incision at mcburney’s point
• 2/3rds of the distance
between the umbilicus and
asis
• through a ‘gridiron’ muscle-
splitting incision
21. RELATE VISCERAL REFERRED PAIN TO THE EMBRYOLOGICAL
DEVELOPMENT OF THE GUT
• FOREGUT PAIN – EPIGASTRIC REGION
• MIDGUT PAIN – PERIUMBILICAL REGION
• HINDGUT PAIN – SUPRAPUBIC REGION
• VISCERAL PAIN IS CAUSED BY ISCHAEMIA,
ABNORMALLY STRONG MUSCLE CONTRACTION,
INFLAMMATION AND STRETCH
• TOUCH, BURNING, CUTTING AND CRUSHING DOES
NOT CAUSE VISCERAL PAIN
22. EXAMPLES OF REFERRED PAIN RELATING TO THE
ABDOMINAL CAVITY
• acute appendicitis
• in early appendicitis the pain begins at the
umbilicus, since the innervation of the
appendix enters the spine at that level
(t10).
• later, as the appendix becomes more
inflamed it irritates the surrounding bowel
wall, localising the pain to the right lower
quadrant(irritation to somatic nerve).
23. Small / Large Bowel Colic
Doubled over in pain.
Small bowel colic Periumbilical (midgut)
Large bowel colic Suprapubic (hindgut)
