Anterior Abdominal Wall

Front 1

boundaries of the abdominopelvic cavity and its subdivision into abdominal & pelvic cavities

Back 1

Abdominal cavity - bounded by:
- diaphragm (roof)
- anterolateral abdominal wall
- posterior abdominal wall
- pelvic inlet (opening between abdominal cavity & pelvic cavity)

Front 2

anterolateral abdominal wall and the nerves that supply it

Back 2

T7-11 (intercostal nn.)
T12 (subcostal n)
L1 (illioinguinal + illiohypogastric nn)

Front 3

name the layers penetrated by a needle passed into the peritoneal cavity through the midline of anterior abdominal wall

Back 3

•Skin
•Superficial fascia
•Deep fascia (very thin)
•Linea alba
•Transversalis fascia
•Extraperitoneal fat
•Parietal peritoneum

Front 4

Neddle through the lateral Abd Wall

Back 4

•Skin
•Superficial fascia
•Deep fascia (very thin)
•External oblique
•Internal oblique
•Transversus abdominis
•Transversalis fascia
•Extraperitoneal fat
•Parietal peritoneum

Front 5

significance of the membranous layer of deep fascia (Scarpa’s fascia)

Back 5

Clinical significance of membranous layer: It forms a self-contained pouch inferiorly that may fill with urine that extravasates from a ruptured urethra in males (arrows indicate path taken by urine in cases of ruptured urethra e.g., straddle injuries).

Sutures through membranous layer  cosmetically better result (strengthens healing wound, reduces skin stretch).

Front 6

structures that converge on the internal aspect of the umbilicus and how they relate to early development

Back 6

- all layers fuse at umbilicus
- • ~LV3/4 level (but variable)
• site of attachment of umbilical cord
• a consolidated scar
• all layers of ant. abdominal wall fused here
• may evert with raised intraabdominal pressure (e.g., ascites or large mass (tumour, foetus)
• abdominal aorta bifurcates about 1cm below and to left

Front 7

muscles of the anterior abdominal walls and state their actions

Back 7

- mm contract to move trunk (flex, rotate & laterally flex the trunk)
- mm contract during forced expiration (pull ribs down, compress abd viscera & force a relaxed diaphragm upward) - mm contract to compress abdominal viscera & increase intra-abdominal pressure (diaphragm also contracts) e.g., lift, strain, expel abdominal contents (vomit, defaecate, childbirth), prior to cough or sneeze
- reflex contraction to protect viscera against injury (“guarding”) e.g., generalised peritonitis  board-like rigidity
- resting muscle tone  support of viscera (loss of muscle tone locally eg nerve damage  visceroptosis)

Front 8

formation of the rectus sheath

Back 8

FUNCTION: retains rectus abdominis muscle and provides added support to the ant abdominal wall

Above arcuate line: ant. layer is formed by aponeurosis of EO & ant part of aponeurosis of IO, post. layer is formed by post part of IO aponeurosis & all of TA aponeurosis
Below arcuate line: ant. layer is formed by all 3 aponeuroses of EO, IO and TA; post. rectus sheath is absent - rectus abdominis muscle is in contact with transversalis fascia

Front 9

significance of enlarged superficial veins on the anterior abdominal wall

Back 9

- can signify liver failure (patent paraumbicialc v.) from portal backflow

Front 10

lymphatic drainage of skin & superficial fascia of trunk wall above and below the umbilicus/iliac crest

Back 10

- below to inguinal
- above to axillary

Front 11

Abdominal Wall:
functions

Back 11

1. expansile 
accommodate considerable changes in volume
2. contractile 
support of contained viscera (resting tone of mm)  move the trunk (eg, rotation, flexion) 
increase the intra-abdominal pressure (eg, straining, or prior to cough /sneeze)

Front 12

Quadrants of Ant Abd Wall

Back 12

Front 13

Regions of the Ant Abd Wall

Back 13

Front 14

Camper's Fascia

Back 14

fatty layer superficial fasica
- continous with the thigh

Front 15

Scrapas Fascia

Back 15

membranous layer of superficial fascia
- ends 1cm below the inguinal ligament where it fuses with deep fascia of the thigh
- It extends into the perineum and is continuous with (dartos) fascia around penis and scrotum and attaches to ischiopubic ramus and posterior edge of perineal membrane.

Front 16

External Oblique

Back 16

Attachments: Lower 8 ribs (ext surface)  linea alba, pubic tubercle, ant ½ iliac crest, inguinal ligament
Action: trunk flexion & contralateral rotation; compress abdominal viscera;
Innervation: T7-T12

Front 17

Internal Oblique

Back 17

Attachments: Thoracolumbar fascia, ant 2/3rd iliac crest, lat 2/3rd ing lig  ribs 10-12, linea alba & pecten pubis via conjoint tendon

Action: trunk flexion, ipsilateral rotation, compress abdominal viscera,

Innervation: T7-L1 (iliohypogastric & ilioinguinal nn) *Gives rise to cremaster muscle (skeletal muscle: contraction  elevates testis)

Front 18

Transversus Abdominis Muscle

Back 18

Attaches: Lower 6 ribs (int surface), thoracolumbar fascia, iliac crest, lat 1/3 ing lig  linea alba & pecten pubis via conjoint tendon
Action: compress & support abdominal viscera,
Innervation: T7-L1 (iliohypogastric &ilioinguinal nn)

Front 19

Rectus Abdominis Muscle

Back 19

Attaches: Pubic symphysis and crest  xiphoid process & cc 5-7
Action: trunk flexion, compress abdominal viscera, stabilise tilt of pelvis (antilordosis)
Innervation: T6/7-12

Front 20

Rectus Sheath Above and below arcuate line

Back 20

Above arcuate line, ant & post layers of rectus sheath are formed by 1 ½ aponeuroses each
Below arcuate line, all 3 aponeuroses pass anterior to rectus abdominis

The superior and inferior epigastric vessels anastomose within the rectus sheath. If the aorta is occluded, collateral supply to the lower parts of body occurs through these arteries. they travel below rectus abdominis

Front 21

Linea alba

Back 21

midline, tendinous raphe (from xiphoid to pubis); formed by aponeuroses of EO, IO & TA of both sides

- the area surgeons love; it does not bleed

Front 22

Fascial Lining of Abdominal Cavity

Back 22

Front 23

Peritoneal folds on internal aspect of anterior abdominal wall

Back 23

1. Falciform ligament, with ligamentum teres in its lower edge, ends at umbilicus.
2. Median, medial & lateral umbilical folds are ridges formed respectively by peritoneum over the urachus (abdominal remnant of allantois), L&R obliterated umbilical artery and L&R inferior epigastric vessels.

The median and medial umbilical folds converge on the umbilicus.
The lateral fold ascends towards rectus abdominis.
- bleeding will occur if the lateral umbilical fold is cut

Front 24

Arterial Supply

Back 24

The superior and inferior epigastric vessels anastomose within the rectus sheath. If the aorta is occluded, collateral supply to the lower parts of body occur through the sup and inf epigastric aa.

Front 25

Venous Supply

Back 25

Deep and superficial veins on anterior abdominal wall anastomose & provide alternative routes to SVC if the IVC is occluded.

Front 26

Prominent Superficial Veins

Back 26

- paraumbilical vein is closed but can reopen in liver failure

Front 27

LN in abd wall

Back 27

Superficial lymph vessels of abdominal wall drain the skin & superficial fascia (to axillary or superficial inguinal lymph nodes) Deep lymph vessels drain muscle & tissues deep to this and drain along arteries to nodes associated with these aa. (eg to lateral aortic, parasternal, external iliac, inguinal nodes)

Front 28

Nerves

Back 28

T7-T11(12) (thoracoabdominal = lower IC nn and subcostal n. (T12) that continue forward & down from IC spaces to abdominal wall L1 = iliohypogastric & ilioinguinal nn. Ilioinginal n. passes through inguinal canal.

Front 29

Clinical Significance of nn

Back 29

Significance: Irritation of lower 6 thoracic nn. can  pain referral to abdominal wall; shingles of these nerves  blisters and pain on thoracic & abd wall. Nerves innervate skin, muscle & parietal peritoneum therefore irritation of parietal peritoneum  reflex mm. spasm, ie. “guarding” of abdominal wall (= attempt to rest and localise the inflammatory process). Generalised peritonitis  board-like rigidity. Rebound tenderness occurs when inflamed parietal peritoneum is stretched - even when that movement is elicited by removing the hand from a distant site. Damage to nerves, e.g., abdominal incision  paralysis of muscles (weak area, unsightly bulge & visceroptosis)

Avoid vertical incisions of lateral part of rectus muscle, which would sever its nerve supply  weakness

Front 30

Abdominal Reflex

Back 30

Abdominal reflex – stroke each quadrant of ant. abdominal wall  reflex mm contraction (umbilicus drawn to side of contraction) – tests segmental nerves (also absent in some forms of brain damage e.g., stroke).

Front 31

Inguinal Canal

Back 31

-
Oblique passageway through the muscles and fascia of the lower anterior abdominal wall
-
Located above the medial half of the inguinal ligament
-
From the deep to the superficial inguinal ring it is about 4cm long - Contains the spermatic cord (male) or the round ligament (female), and the ilioinguinal nerve

Front 32

Layers of the Inguinal Canal

Back 32

1. EO aponeurosis
2. IO muscle
3. TA muscle
4. transversalis fascia

Front 33

Boundaries of the inguinal canal

Back 33

Floor Inguinal ligament
Roof Internal oblique and transversus abdominis muscles
Anterior External oblique aponeurosis and internal oblique muscle
Posterior Transversalis fascia and conjoint tendon

Front 34

The conjoint tendon

Back 34

Formed from the lower part the transversus abdominis muscle
Inserts into the crest of the pubis and lies immediately behind the superficial inguinal ring
Serves to protect an otherwise weak point in the abdominal wall

Front 35

Shutter-like effect of transversus abdominis and internal oblique

Back 35

Transversus abdominis and internal oblique close like a shutter on the inguinal canal in response to increased intra-abdominal pressure, serving to protect against herniation.

Front 36

Q.What is the relationship between a previous appendectomy and a right sided inguinal hernia?

Back 36

A. The right ilioinguinal nerve (L1) may be damaged during an open appendectomy  weakness of the shutter-effect of the arching fibres of transversus abdominis and internal oblique

Front 37

Spermatic Cord:
Contents

Back 37

3 arteries: cremasteric, deferential artery, testicular
3 nerves: genital branch of the genitofemoral nerve, autonomic, ilioinguinal
3 fascial layers: external spermatic, cremasteric, internal spermatic
3 other structures: pampiniform plexus, vas deferens, testicular lymphatics

Front 38

Coverings of the spermatic cord and testes and their origns

Back 38

Transversalis fascia  internal spermatic fascia
Internal oblique muscle  cremasteric fascia &muscle
External oblique aponeurosis  external spermatic fascia

Front 39

Anatomical location of deep inguinal ring

Back 39

The deep inguinal ring is located superior to the pulse of the femoral artery

Front 40

Conjoint tendon

Back 40

The conjoint tendon is formed by the lower half of transversus abdominis and serves to protect an otherwise weak point in the abdominal wall. It lies behind the superficial inguinal ring.

Front 41

Hernias

Back 41

A hernia is a protrusion through a structure that normally contains it

Front 42

Parts of a hernia

Back 42

(1) Hernial sac Usually a pouch of peritoneum
(2) Contents Generally structures from the abdominal cavity e.g. fat, omentum or bowel
(3) Coverings Contains layers from the abdominal wall through which the hernial sac passes

Front 43

2 types of hernias

Back 43

If the neck of the sac is narrow, adhesions & strangulation are common

Front 44

Inguinal Hernias

Back 44

Front 45

Direct and Indirect Hernias

Back 45

Front 46

Hesselbach's Triangle bounded by

Back 46

1. rectus abdominis
2. inferior epigastric a.
3. Inguinal ligament

Front 47

Indirect inguinal hernia

Back 47

-passes through deep inguinal ring lateral to inferior epigastric artery
-most common type of inguinal hernia (2/3rd)
-occurs in young & old
-males > females;
-may extend through superficial inguinal ring into scrotum
-narrow neck (important in strangulations)

Front 48

Direct Inguinal Hernia

Back 48

-passes through weakness in anterior abdominal wall via Hesselbach’s triangle medial to inferior epigastric artery
-through or around a weak conjoint tendon
-age >40 years
-less common than indirect hernia
-rarely enters scrotum
-wide neck of hernia (rarely strangulates)
-lump at superficial inguinal ring

Front 49

Femoral Hernia

Back 49

- Passes through femoral ring into thigh
- Protrudes through saphenous opening in fascia lata
- More common in females than males (4:1)
- Femoral ring forms neck of the hernia. Boundaries:
- Inguinal ligament (anterior)
- Pectineus muscle & fascia (posterior)
- Femoral vein (lateral)
- Lacunar ligament (medial)

- Sharp margin of the lacunar ligament can cause strangulation of the hernia (surgical emergency)

Front 50

Summary Slide of Hernias

Back 50

Front 51

Examination: inguinal & femoral hernias

Back 51

Front 52

other abdominal hernias

Back 52