1. Anterior abdominal wall (IRS)
Objectives
Describe the anterior abdominal wall:
musculature and fascial layers
formation of rectus sheath and its contents
relevance to surgical incisions;
Describe the dermatomes and concept of referred pain
Describe the deep and superficial inguinal rings
Describe the boundaries of inguinal canal

2. Anterior abdominal wall
DR. WAI WAI KYI
Feb 2012

3. The abdominal wall Boundaries of the abdomen Superior - diaphragm Inferior - pelvic inlet Anterior - anterior abdominal wall Posterior - lumbar vertebrae, upper part of bony pelvis, psoas and quadratus lumborum muscles.

4. Organs by Abdominal Quadrant
Right
Left
Upper
Small and Large Intestine Lower part of Kidney Half of Bladder, Female Reproductive Organs
Small and Large Intestine
Lower part of Kidney Half of Bladder, Appendix, Female Reproductive Organs
Stomach, Tail of Pancreas
Tail of Liver Small and Large Intestine Upper Part of Kidney
Liver, Gallbladder, Stomach (Small Part) Small and Large Intestine Head of Pancreas Upper Part of Kidney
Lower

5. Layers of anterior abdominal wall
Skin
Fascia
Camper's fascia - fatty superficial layer.
Scarpa's fascia - deep fibrous layer.
Muscle
Rectus abdominis
External oblique muscle
Internal oblique muscle
Transverse abdominal muscle
Fascia transversalis
Peritoneum

6. Four Quadrants:
Midsaggital or median plane
Transumbilical plane - passes through the umbilicus and disc
between L3 and L4

7. To describe the location of
organs easily, the
abdominopelvic cavity may be
divided into nine regions
by drawing four imaginary lines.
Nine Regions:
Subcostal plane - passing
thro’ the inf. border of the 10th
costal cartilages (LV3).
Transtubercular plane –
passing thro’ the tubercles of
the iliac crests (LV5).
Transpyloric plane- Sometimes
used; halfway between the
jugular notch and the upper
border of the symphysis pubis.
Midclavicular plane

9. Layers of the anterior abdominal wall
Skin
Superficial fascia
Camper's fascia dartos muscle
Scarpa's fascia  Colles' fascia
Muscle
External oblique
Internal oblique
Transversalis abdominus
Transversalis fascia
Peritoneum

11. Superficial fascia is divided
into:
Superficial fatty layer (Camper's)
Deep membranous layer (Scarpa's)
• Camper's s fascia is continous with superficial fascia over the rest of
body
• Scarpa's fascia fades out laterally and above

12. Superficial veins of anterolateral abdominal wall
Superficial fatty (Camper's)
contains superficial veins.
Above - via lateral thoracic vein  into axillary vein
Below  via superficial epigastric + great saphenous veins into femoral vein
Paraumbilical  portal

13. Lateral thoracic
Thoracoepigastric
Paraumbilical
Sup. circumflex iliac
Sup. epigastric

14. Superficial lymphatics of anterolateral abdominal wall
Superior to the umbilicus drain to the axillary lymph nodes; a
few drain medially and deeply to the parasternal and anterior
diaphragmatic lymph nodes.
Inferior to the umbilicus drain to the superficial inguinal lymph
nodes.

16. Cutaneous nerve supply to anterior abdominal wall
Anterior rami of lower 6 thoracic (T7-T12) lower 5 intercostal + subcostal nerves
1st lumber nerves  iliohypogastric + ilioinguinal

17. Arteries 5 intercostal arteries subcostal arteries 4 lumbar arteries
Superior epigastric artery—internal thoracic artery
Inferior epigastric artery -external iliac artery
Deep iliac circumflex artery- external iliac artery

18. Langer's lines of the skin
Langer's lines, also called cleavage lines correspond to the alignment of collagen fibers within the dermis. Usually, a surgical cut is carried out in the direction of Langer's lines, and incisions made parallel to Langer's lines generally heal better and produce less scarring.

19. Dermatomes - Relationship between the spinal nerve & skin
Myotomes - Relationship between the spinal nerve & muscle
Spinal Cord Segmental Dermatomes
Dermatome ( Greek word= skin cutting.
A dermatome is an area of the skin supplied by nerve fibers
originating from a single dorsal nerve root. 
The dermatomes are supplied as follows:
T7 - epigastrium
T10 -  umbilicus
L1 - inguinal ligament

22. Muscles of the Anterolateral Abdominal Wall

23. Muscles The muscles of the anterior and lateral abdominal walls are:
External oblique
Internal oblique
Transversus abdominis
Rectus abdominis
Pyramidalis

24. Rectus abdominis muscle
This is a long, broad, strap-like muscle and is the principle vertical muscle of the anterior abdominal wall.
O: pubic symphysis and pubic crest.
I: xiphoid process and 5th to 7th costal cartilages.
N: ventral rami of inferior six thoracic nerves.
Act: Flexes vertebral column, depresses ribs and compresses abdomen.
The two muscles are separated by the linea alba and lie close together inferiorly.
The rectus abdominis is three times as wide superiorly as it is inferiorly.

25. Rectus abdominis muscle ( Cont.)
Linea semilunaris is a curved line or groove (convex laterally) that extends from the 9th costal cartilage to the pubic tubercle. This indicates the lateral border of the rectus abdominis muscle.
Enclosed in the rectus sheath
The anterior layer of the rectus sheath is firmly attached to the rectus muscle at three or more tendinous intersections.They are usually located at the level of the xiphoid process, umbilicus, and halfway between this structures.

26. External oblique muscle
O: External surfaces of 5th to 12th ribs.
I: Linea alba, pubic tubercle and anterior half of the iliac crest.
N: Inferior six thoracic nerves and subcostal nerves.
Act.Compresses abdomen; depresses ribs; Jointly: flex vertebral column; Individually: rotation and lateral flexion.
Muscle fiber direction is antero-inferior (like external intercostals - hands in pocket).
EO aponeurosis ends medially in the linea alba.
Inferiorly form the inguinal ligament between the anterior superior iliac spine and the pubic tubercle.
superficial inguinal ring.an opening in the aponeurosis Just superior to the medial part of the inguinal ligament.
Some fibres of the inguinal ligament cross the linea alba and attach to the opposite pubic crest. These fibres form the reflex inguinal ligament.

27. - It arches over spermatic cord (or round lig. of uterus), then
The Internal Oblique Muscle
O: thoracolumbar fascia, anterior two-thirds of iliac crest, and lateral half of inguinal ligament.
I: inferior borders of last three ribs, linea alba, and the pubic crest via the conjoint tendon.
N: ventral rami of inferior six thoracic and first lumbar nerves.
Act. The same as EO muscle
The aponeurosis splits to form a sheath for the rectus abdominis muscle.
Lower, free border of IO
- It arches over spermatic cord (or round lig. of uterus), then
descend behind to attach to pubic crest and pectineal line
- Near their insertion it is joined by lowest tendinous fibres
fromTA to form conjoint tendon
Function of conjoint tendon -to strengthen the medial 1/2 of
posterior wall of inguinal canal.

28. Transversus abdominis This is the innermost of the three flat abdominal muscles. O: Internal surfaces of 7th to 12th costal cartilages, thoracolumbar fascia, iliac crest, and lateral third of inguinal ligament. I: Linea alba (with aponeurosis of internal oblique), pubic crest, and pecten pubis (via conjoint tendon). N: Ventral rami of inferior six thoracic and first lumbar nerves. A. Compresses abdominal cavity

29. Pubic Symphysis

30. Layers of the Abdominal Wall

32. Rectus sheath
Long fibrous sheath which encloses rectus abodminis and
pyramidalis (if present)
Rectus sheath is formed by:
aponeuroses of 3 lateral abdominal muscles
Aponeurosis of IO splits into 2
• anterior lamina fuses with aponeurosis of EO • posterior lamina fuses with aponeuorsis of TA
Above the Arcuate line (at level of anterior superior iliac spine)
All 3 aponeuroses pass anteriorly to rectus muscle so, sheath deficient posteriorly below this level.
Posterior wall of rectus sheath
it's not attached to rectus abdominis muscle.

33. Rectus sheath
Above semicircular line of Douglas/Arcuate line (midway between symphysis pubis and umbilicus):
Anterior rectus sheath = external oblique aponeurosis and anterior lamina of internal oblique aponeurosis. Posterior rectus sheath = posterior lamina of internal oblique aponeurosis and aponeuorsis of TA.

34. Below semicircular line of Douglas: Anterior rectus sheath = aponeurosis of external, internal oblique, transversus Posteriorly- deficient below this level, only transversalis fascia is present. Arteries: Superior epigastric (branch of internal thoracic), inferior epigastric (branch of external iliac), both arteries anastomose and lie behind the rectus muscle.

35. Rectus sheath contains:
Rectus sheath encloses rectus abdominis and pyramidalis muscle (if present)
Contains anterior rami of lower six thoracic nerves
Also contains superior epigastric artery (continuation of the internal thoracic artery) and inferior epigastric artery (from external iliac artery).
Lymph vessels

36. Arcuate line
lower, crescent-shaped edge of the posterior wall of rectus sheath. At this level inferior epigastric vessels enter the rectus sheath
Linea alba
A fibrous band, made by the fusion of all 3 aponeuroses with their fellows of opposite side in middle
Extends from xiphoid to pubic symphisis

38. Midline General access. Usually skirts the umbilicus
Midline General access. Usually skirts the umbilicus. Quick and bloodless Paramedian General access. Left or right according to requirements. Kocher (Subcostal) Biliary or hepatic procedures. May be extended across to a left subcostal incision to give useful access to the stomach and pancreas. McBurney – 1/3 of the way along the line from the anterior superior iliac spine to the umbilicus Appendicectomy. Muscle layers are split, rather than cut. Transverse Skin incision crosses fewer dermatomes General access. Almost always used in infants, and often in adults. Rutherford Morison Access to sigmoid colon and pelvis, particularly if the midline is very scarred from previous surgery. Pfannenstiel For Caesarian sections and urological surgery. Good cosmetic result but gives no access outside the pelvis

39. Layers of the abdominal wall, inguinal canal and their relations to
the spermatic cord and testies

40. Descent of Testis Through Inguinal Canal to Scrotum
Transversalis fascia–
deep ring/internal
spermatic fascia
Peritoneum forming processus
vaginalis/tunica vaginalis testis
Transversus
abdominis
Internal oblique—
cremaster muscle
External oblique—
superficial ring/
external spermatic
fascia
Gubernaculum

41. Layers of scrotum skin dartos muscle external spermatic fascia cremastric fascia internal spermatic fascia
peritoneum, tunica vaginalis
Coverings of spermatic cord (Spermatic fascia)
3 concentric layers of fascia derived from layers of anterior
abdominal wall: • external spermatic fascia -derived from EO • cremasteric fascia -derived from IO • internal spermatic fascia- derived from fascia transversalis
attached to margins of deep inguinal
ring

42. Structures of spermatic cord • vas deferens • artery of the ductus deferens (from the inferior vesical artery ) • testicular artery (from aorta) • testicular veins (pampiniform plexus) • testicular lymph vessels • autonomic nerves • remains of processus vaginalis • cremasteric artery (from the inferior epigastric artery). • genital branch of genitofemoral nerve (supplies cremaster muscle)

44. The Inguinal Region

45. 4cm tunnel in lower, anterior abdominal muscles and lies
The Inguinal Region
It is an area of weakness in the anterior abdominal wall because
of the prenatal penetration of the wall by the testis and the
spermatic cord.   .
Inguinal canal
4cm tunnel in lower, anterior abdominal muscles and lies
parallel to and immediately above, the inguinal ligament.
It runs downwards and medially between the deep and
superficial rings.
Walls of the Inguinal Canal:
Anterior
Posterior
Superior
Inferior

46. Inguinal (Hesselbach's) triangle
An anatomic area of the abdominal wall bounded by:
Suprolateral:   inferior epigastric vessels
Medial:  lateral margin of the rectus muscle
Inferior:  The inguinal ligament /Poupart's ligament
Clinical significance
Direct inguinal hernias leave the abdomen through this triangle.

47. Contents of Inguinal Canal
Spermatic Cord (male) or Round ligament (female)
Ilioinguinal nerve
Genital branch of the genitofemoral nerve.

48. Superficial Inguinal Ring
Triangular -shaped defect in the aponeurosis of the external oblique
Immediately above and medial to the pubic tubercle
Margins give origin to the external spermatic fascia
Physical exam - to differentiate bet. direct & indirect inguinal hernias

49. Deep Inguinal Ring
3cm superior to the midpoint of the inguinal ligament.
Lateral to the inferior epigastric vessels
Margins of ring give origin to the internal spermatic fascia

50. Inguinal Anatomy

51. Walls of the inguinal canal
Anterior wall
Aponeurosis of ext. oblique
♦ Reinforced laterally by the fibres of the internal oblique
■ Strongest where it lies opposite the weakest part of the
posterior wall (deep ring).

52. Walls of the Inguinal Canal
Posterior wall
Formed throughout by the transversalis fascia
♦ reinforced medially by the conjoint tendon.
■ Strongest where it lies opposite the weakest part of the anterior wall (superficial ring).

53. Walls of the Inguinal Canal
Inferior (floor)
The superior surface of the inguinal ligament and the lacunar ligament.
Superior (roof)
Arching lowest fibers of the Int. oblique and transversus
abdominis muscles.

54. Lacunar ligament (Gimbernat’s ligament)
Medial curved fibres of inguinal ligament that pass upwards and
backwards to attach to pectineal line .
Pectineal ligament
A thickening of periosteum

55. Two important physiolgical mechanismsShutter and Closure mechanims protect the formation of inguinal herniae with increased abdominal pressure.
The arching fibres of the internal oblique and transversus abdominis contract when the muscles of the abdomen contract. This acts as a shutter on the posterior wall to protect it from herniation. This is termed the Shutter Mechanism.
In addition this contraction also narrows the deep ring. The narrowing of the deep ring is termed the Closure Mechanism.

56. Indirect Inguinal Hernia through Inguinal Canal
Congenital (or adult)
Through inguinal canal
(and deep ring)
Lateral to inferior
epigastric artery
Could be in patent
processus vaginalis

57. Direct inguinal hernia
Enter the inguinal triangle
NOT through the inguinal
canal
Medial to inferior
epigastric artery X

58. Above and medial to the pubic tubercle
The hernial sac thus lies inferior and lateral to the pubic tubercle

59. Inguinal (Hasselbach's) triangle

60. b

61. Urinary extravasation
Rupture of spongy urethra is common in straddle injury that
results in extraperitoneal extravasation of urine within the
superficial perineal pouch and extending into the scrotal, penile,
and fatty layer of subcutaneous connective of the lower anterior
abdominal wall areas.
Any fluid (blood, urine, or pus) that is within the superficial pouch will be limited by Colle’s fascia and its attachments.
Urinary extravasation

62. THANK YOU