6 Abdominal wall, inguinal region and hernias 1

Question 1

What structures are beneath the 4 quadrants of the abdomen?

Answer 1

• RUQ: Liver and gall bladder
• RLQ: Ileum, caecum, appendix
• LUQ: Jejunum
• LLQ: Sigmoid colon

Question 2

Which 2 lines are used to determine the 4 quadrants of the abdomen? And where do they lie or pass through?

Answer 2

1. Transumbilical plane - lies at the level of the umbilicus corresponding to the L3/4 intervertebral disc
2. Median plane -
   passes through the xiphoid process & pubic symphysis

Question 3

Which 4 lines are used to determine the 9 regions of the abdomen? And where do they lie or pass through?

Answer 3

1. Midclavicular Lines (2)
   - passes through midpoint of clavicle
2. Subcostal Plane -
   lies at L3 vertebra level uniting the lowest point of the costal margins - level of the 10th CCs
3. Transtubercular/ intertubercular plane -
   lies at the level of the L5 vertebra uniting the two iliac tubercles

Question 4

What is the umbilicus?

Answer 4

A scar representing the site of attachment of the umbilical cord in the foetus

Question 5

How is the superficial fascia of the abdominal wall divided?

Answer 5

1. Superficial fatty layer - Camper’s fascia

2. Deep membranous layer - Scarpa’s fascia

Question 6

What is fascia?

Answer 6

• “Packing tissue” allowing movement of structures in relation to each other but without being restrictive
• Some provides muscle attachment

Question 7

What is the composition of the internal fascia in the abdominal wall?

Answer 7

1. There are very thin, negligible layers of fascia between the muscles
2. Deep to the muscles (but outside the peritoneum), there is a layer of endo-abdominal or transversalis fascia
3. Variable extraperitoneal fascia which is immediately external to the peritoneum

Question 8

What are the 2 layers of the superficial fascia/ subcutaneous tissue of the perineum?

Answer 8

1. Superficial fatty layer -Camper’s fascia

2. Deep membranous layer - Colles’/perineal fascia

Question 9

What are Scarpa’s fascia and Camper’s fascia continuous with in the perineum?

Answer 9

• Scarpa’s fascia is continuous with Colles’/perineal fascia
• Camper’s fascia is continuous with the superficial fatty layer of the
superficial fascia/subcutaneous tissue of the perineum

Question 10

In the abdomen, what fascia layers are found deep to the muscle layer?

Answer 10

1. Transversalis fascia

2. Extraperitoneal fascia

Question 11

Where does thoracolumbar fascia pass from and to? What does it give origins to? What may be at risk?

Answer 11

Passes from the iliac crest –> 12th rib in 3 layers (anterior, middle & posterior) that surround the back muscles & fuse together to give origin to the transversus abdominis & internal oblique muscles but not external oblique (free edge posteriorly - lumbar hernia)

Question 12

What does transversus abdomens and internal oblique arise from?

Answer 12

Thoracolumbar fascia

Question 13

What is transversals fascia (undo-abdominal fascia)?

Answer 13

Thin layer of fascia (connective tissue)
• lines the transversus abdominis muscle
• continuous with a similar layer lining the diaphragm & the iliacus muscle

Question 14

What is extraperitoneal fascia?

Answer 14

Thin layer of fascia (connective tissue)
• contains a variable amount of fat
• lies between the transversalis fascia & the parietal peritoneum

Question 15

What lines the walls of the abdomen?

Answer 15

Parietal peritoneum -

thin serous membrane that encloses peritoneal cavity

Question 16

What are the layers in the abdomen?

Answer 16

1. Skin
2. Superficial fascia:
   • Fatty layer (Camper’s)
   • Membranous layer (Scarpa’s)
3. External oblique m
4. Internal oblique m
5. Transversus abdominis m
6. Transversals fascia
7. Exztraperitoneal fascia
8. Parietal peritoneum

Question 17

What are the anterior abdominal wall muscles? (4)

Answer 17

3 broad, thin sheets
(sup to deep):
1. External oblique
2. Internal oblique
3. Transversum abdominis

A vertical muscle:
4. Rectus Abdominis (and Pyramidalis)

Question 18

What are the functions of the anterior abdominal wall muscles?

Answer 18

1. Support abdominal contents and raise intra-abdominal pressure, withstanding pressure from descent of the diaphragm
2. Support vertebral column, flexing, laterally flexing and rotating the trunk against resistance
3. Respiration

Question 19

What 2 points are on the same coronal plane on a pelvis?

Answer 19

1. Anterior superior iliac spine

2. Pubic tubercle

Question 20

Where does the arcuate line continue from?

Answer 20

Pectineal line

Question 21

External oblique:
Attachments?
Fibre direction?
Nerve supply?

Answer 21

1. Attachments:
   • Lower 8 ribs
   • Lateral lip of iliac crest • Aponeurosis to linea alba via rectus sheath
   • Forms the inguinal ligament
2. Fibre direction:
   • Downwards and medially
3. Nerve supply:
   • T7-12

Question 22

What is the inguinal ligament? What is it’s attachments?

Continues as?

Answer 22

• Inrolled, inferior edge of external oblique
• From ASIS to pubic tubercle
• Continues as lacunar and pectineal ligaments

Question 23

What is the superficial ring?

Answer 23

Triangular opening in external oblique aponeurosis with its base at the pubic crest

Question 24

Internal oblique:
Attachments?
Fibre direction?
Nerve supply?

Answer 24

1. Attachments
   • Thoracolumbar fascia
   • Iliac crest (inside external oblique)
   • Lateral 2/3rds of inguinal ligament
   • Lower 3 or 4 ribs & costal cartilages
   • Aponeurosis to linea alba (xiphoid to pubic
   symphysis) via rectus sheath
   • Pubic crest behind the superficial inguinal
   ring via conjoint tendon (with transversus abdominis)
2. Fibre direction:
   • Upwards & medially to ribs, but downwards to conjoint tendon
3. Nerve supply:
   • T7 to T12 plus L1 via the iliohypogastric nerve
   to the fibres that form the conjoint tendon

Question 25

What is the consequence of injury to the iliohypogastric nerve?

Answer 25

* May weaken the conjoint tendon | * Predispose to inguinal hernias

Question 26

Transversus abdominis: Attachments? Fibre direction? Nerve supply?

Answer 26

1. Attachments • Thoracolumbar fascia • Iliac crest (inside internal oblique) • Lateral 1/3rd or 1/2th of inguinal ligament • Lower 6 ribs & costal cartilages • Aponeurosis to linea alba (xiphoid to pubic symphysis) via rectus sheath • Pubic crest behind the superficial inguinal ring via conjoint tendon (with internal oblique) 2. Fibre direction: • Transversely to ribs, linea alba & conjoint tendon 3. Nerve supply: • T7 to T12 plus L1 via the iliohypogastric nerve to the fibres that form the conjoint tendon

Question 27

What is the conjoint tendon formed from? Attachements?

Answer 27

* Formed from the aponeuroses of internal oblique & transversus abdominis * Attaches to the pubic crest & pectineal line behind the superficial inguinal ring therefore supports the ring

Question 28

Rectus abdominis: Attachments? Fibre direction? Nerve supply?

Answer 28

``` 1. Attachments • Costal cartilages of ribs 5 to 7 • Xiphoid process • Pubic symphysis • Pubic crest (behind the conjoint tendon & superficial inguinal ring) • Pectineal line ``` 2. Fibre direction: • Vertically but interspersed with tendinous intersections 3. Nerve supply: • T7 to T12

Question 29

What is pyramidalis?

Answer 29

Small triangle anterior to rectus abdominis from the pubic crest to linea alba

Question 30

What forms the rectus sheath?

Answer 30

* Each rectus abdominis is enclosed anteriorly & posteriorly between the bilaminar aponeuroses of the external oblique, internal oblique & transversus abdominis that form the rectus sheath * In the midline they fuse as the linea alba (relatively avascular: good for entering the abdomen, but poor healing!)

Question 31

What happens to the rectus sheath and inferior epigastric vessels at the arcuate line and below?

Answer 31

* All the aponeuroses pass anteriorly & the posterior sheath ends * Inferior epigastric vessels enter behind rectus abdominis

Question 32

``` Inguinal canal: What is it? Created by? Openings? Contains? ```

Answer 32

1. Oblique passage, (4 to 6cm long) through the anterior abdominal wall connecting the abdominal cavity to the scrotum in males or the labia majora in females 2. "Tunnel" created by the descent of the testis “pushing” through the 3 layers of muscle 3. The inguinal canal has two openings: (1) Deep inguinal ring (2) Superficial inguinal ring • Each “protected” by 2 of the 3 muscles (or aponeuroses) ``` 4. Contents: • Vas/ductus deferens in males • Testicular artery in males • Round ligament of uterus in females • Genital branch of genitofemoral nerve (L1/2) • Ilioinguinal nerve (L1) ```

Question 33

Superficial inguinal ring: Location? Structural features?

Answer 33

* Triangular opening in the external oblique aponeurosis with its base at the pubic crest * Medial & lateral (stronger) crura * Supported from behind by the conjoint tendon (combined tendons of internal oblique & transversus abdominis)

Question 34

``` Deep inguinal ring: What is it? Overlain by? Transmits which structures? Position? ```

Answer 34

1. Opening in or evagination of transversalis fascia 2.Overlain (anteriorly) by: • Internal oblique • External oblique 3. Transmits: • Vas/ductus deferens • Gonadal vessels (in spermatic cord) 4. Lies lateral to the inferior epigastric vessels about 1cm above the mid-point of the inguinal ligament (midway between the ASIS & pubic tubercle/ midway between the ASIS & pubic symphysis -mid-inguinal point)

Question 35

What are the inguinal canal boundaries?

Answer 35

1. Anterior: • External oblique • Internal oblique laterally 2. Posterior: • Conjoint tendon medially • Transversalis fascia laterally 3. Roof: • Arching fibres of internal oblique and • Transversus abdominis 4. Floor: • In rolled lower edge of external oblique (inguinal ligament) • Strengthened medially by lacunar ligament

Question 36

What are the mechanics of hernias?

Answer 36

1. On coughing & straining (e.g. micturition, defecation & parturition) • The arching lowest fibres of the internal oblique & transversus abdominis muscles contract flattening out the arched roof of the inguinal canal so that it is lowered toward the floor • The roof may actually compress the contents of the inguinal canal against the floor so that the canal is virtually closed 2. When great straining efforts may be necessary (e.g. defecation & parturition) • The person naturally tends to assume the squatting position • The hip joints are flexed & the anterior surfaces of the thighs are brought up against the anterior abdominal wall • By this means the lower part of the anterior abdominal wall is protected by the thighs

Question 37

In males, what is most susceptible to the development of hernias?

Answer 37

Inguinal region

Question 38

What is a hernia?

Answer 38

Protrusion of a viscus through the wall of its containing cavity

Question 39

What is the normal location of an inguinal and femoral hernia?

Answer 39

* Inguinal hernia -above & medial to the pubic tubercle | * Femoral hernia - passes through the femoral canal & appears below & lateral to the pubic tubercle

Question 40

What is a direct inguinal hernia?

Answer 40

* Through the posterior wall of the inguinal canal medial to the inferior epigastric vessels * Not covered by layers of spermatic fascia

Question 41

What is an indirect inguinal hernia?

Answer 41

* Through the deep inguinal ring (persistent processus vaginalis) lateral to the inferior epigastric vessels (usually congenital or pre-adolescent but can be any age) * Maybe in the processus vaginalis & within the coverings of the spermatic cord * Bowel in the spermatic cord, covered by parietal peritoneum, passing through the deep inguinal ring of transversalis fascia & therefore covered by internal, cremasteric & external spermatic fascia passing lateral to the inferior epigastric vessels

Question 42

What is Hesselbach's/ Inguinal triangle?

Answer 42

• Direct inguinal hernias • Usually a piece of fat or small bowel from inside the peritoneal cavity, therefore covered by parietal peritoneum, pushing against a weakened conjoint tendon (usually in mature adult male)

Question 43

What forms the internal spermatic fascia at deep inguinal ring?

Answer 43

Transversalis fascia

Question 44

What forms the external spermatic fascia?

Answer 44

External oblique

Question 45

Which type of inguinal hernia is not covered by layers of the spermatic fascia?

Answer 45

Direct inguinal hernia

Question 46

What occurs in more advanced direct inguinal hernia?

Answer 46

* Pushing ahead of the peritoneum, transversalis fascia & combined transversus abdominis with internal oblique (conjoint tendon) & through the superficial inguinal ring (in external oblique & extending as external spermatic fascia) to enter the scrotum * Ends up in scrotum, parallel to spermatic cord & with its own coverings of peritoneum, transversalis fascia, conjoint tendon & external oblique as external spermatic fascia having passed medial to the inferior epigastric vessels

Question 47

Where is cremasteric fascia from?

Answer 47

Transversus abdominis and internal oblique

Question 48

When will hernias increase in size?

Answer 48

On coughing or straining

Question 49

When do hernias reduce in size or disappears?

Answer 49

When relaxed or supine

Question 50

How will a hernia that causes obstruction present?

Answer 50

* Colicky abdominal pain, distension & vomiting may occur) * It will be tense, tender & irreducible

Question 51

How will a hernia that causes strangulation present?

Answer 51

Lump will become red & tender