Lecture 4 - Hernias

Question 1

Visceral pain

Answer 1

Pain that results from:

• Visceral stretching
• Visceral inflammation
• Visceral ischaemia

No somatic innervation therefore pain is:

• poorly localised
• often in midline

Nausea
Vomiting
Sweating

Question 2

Spinal level of sympathetic innervation to gut

Answer 2

T5- L2

Question 3

How are the presynaptic splanchnic nerves formed?

Answer 3

The preganglionic sympathetic fibres pass through the sympathetic chain without synapsing.

They amalgamate to form the presynapytic splanchnic nerves

Question 4

3 presynaptic splanchnic nerves

Answer 4

Greater splanchnic nerve (T5 - T9)
Lesser splanchnic nerve (T10-T11)
Least splanchnic nerve (T12)

Question 5

4 prevertebral ganglia

Answer 5

Coeliac
Renal
Superior mesenteric
Inferior mesenteric

Question 6

Foregut pain

Answer 6

T5-T9 - Greater splanchnic nerve
Midline epigastric pain
Poorly localised

From: 
Liver
Gallbladder,
Stomach  
Spleen
Kidney

Question 7

Midgut pain

Answer 7

1. E.g. Caecul volvulus stimulates general visceral afferents
2. Afferents to superior mesenteric ganglion
3. To lesser splanchnic nerve (T10-T11)
4. Sympathetic chain
5. Dorsal horn of spine
6. Converge with somatic afferents at T10-T11
7. Brain interprets T10 - T11 dermatome pain in the peri-umbilical area

Question 8

Hernia

Answer 8

Protrusion of part of the abdominal contents beyond the confines of the normal abdominal wall

Question 9

Types of hernias

Answer 9

Direct
Indirect

Incarcerated
Not incarcerated

Question 10

Hernias that are not incarcerated

Answer 10

Fullness/ swelling
Gets larger when intraabdominal pressure increases
Aches

Question 11

Incarcerated hernias

Answer 11

Cannot be pushed back
Painful
Nausea and vomiting + signs of bowel obtruction
Systemic problems- bowel becomes ischaemic due to compromised blood supply

Question 12

Causes of hernias

Answer 12

Weakness in the containing cavity

• congenital
• post surgery (incisional hernia)
• Normal points of weakness

Anything that increases intra- abdominal pressure:

• Obesity
• Weightlifting
• Chronic constipation or coughing (smoker)

Question 13

Components of a hernia

Answer 13

Sac- pouch of peritoneum

Contents - structure within the abdominal cavity e.g. bowel or omentum

Coveringss - layers of the abdominal wall through which the hernia has passed

• External oblique
• Internal oblique
• Transversus abdominis
• Transversalis fascia

Question 14

Weaknesses of the abdominal wall

Answer 14

Femoral canal
Inguinal canal
Previous incisions
Umbilicus

Question 15

Inguinal canal

Answer 15

Oblique passage through the lower abdominal wall.

In males - abdomen to the testes where the testes passed through the inguinal canal from the abdomen to the scrotum

In females - Round ligament goes from the uterus to the labrium majora

Question 16

Processus vaginalis

Answer 16

Pouch of peritoneum in males that obliterates once the testes have moved down.

Becomes the tunica vaginalis

Question 17

Gubernaculum

Answer 17

Condensed band of mesenchyme that links the inferior portion of the testes to the labioscrotal swelling

Becomes the scrotal ligament

Question 18

What occurs if the processus vaginalis doesn’t close?

Answer 18

There is a connection between the peritoneal cavity and the scrotum which can be the site of fluid collection and infection

Question 19

Borders of the inguinal canal

Answer 19

Anterior wall - External oblique

Posterior wall - Transversalis fascia and conjoint tendon

Medially = internal oblique and transversus abdominis

Floor - Inguinal ligament and lacunar ligament medially

Roof - Conjoint tendon

Question 20

Indirect hernias

Answer 20

Travel through the deep ring
Traverse the inguinal canal and exit the superficial ring

If it exits the superficial ring, can cause a scrotal hernia if the processus vaginalis is patent

Question 21

Direct hernias

Answer 21

Bulges directly through the abdominal wall through Hasselbach’s triangle in the vicinity of the superficial inguinal ring

Question 22

Percentage of abdominal hernias that are inguinal

Answer 22

75%

Question 23

Percentage of hernias that are indirect and the proportion of males to females

Answer 23

50%

Males 7x more likely

Question 24

Percentage of abdominal hernias that direct

Answer 24

25%

Question 25

Which type of hernia protrudes laterally to the inferior epigastric vessels?

Answer 25

Indirect

Question 26

Which type of hernia protrudes medially to the inferior epigastric vessels?

Answer 26

Direct

Question 27

Borders of Hesselbachs triangle

Answer 27

Medial - Rectus abdominis Roof - Inferior epigastric vessels Floor - inguinal ligament

Question 28

Femoral hernias

Answer 28

More common in females Easily incarcerated and irreducible Contents protrudes through the femoral ring of the femoral canal out of the saphenous ring

Question 29

Borders of the femoral ring

Answer 29

Laterally - Femoral vein | Medially - Lacunar ligament

Question 30

Omphalocele (4)

Answer 30

Failure of the midgut to return to the abdomen during development Viscera persists outside the abdominal cavity within the umbilical ring covered in peritoneum Feeding can occur The abdominal cavity may not grow to correct the size to accommodate the viscera

Question 31

How to treat an omphalocele

Answer 31

Can surgically operate and push viscera back in Mortality rate is high as often associated with other genetic problems

Question 32

Gastroschisis (6)

Answer 32

Defect in the ventral abdominal wall The abdominal viscera are not covered in peritoneum - exposed to amniotic fluid Problems with gut development - atresia, inflamed or short Feeding problems Better survival rates that omphalocele as not associated with other genetic factors Defect can close at birth - push back in stepwise

Question 33

Umbilical hernia

Answer 33

Commonly in infants Hernia bulges at the umbilicus Not painful 80-90% close by 3 yrs old

Question 34

Paraumbilical hernia

Answer 34

Acquired in adults Through linear alba in the region of the umbilicus More common in females Caused by obesity as there is an increase in intra-abdominal pressure

Question 35

Presentation of para umbilical hernias

Answer 35

Based around what happens to the loops of bowel - if trapped: Pain Vomiting Sepsis

Question 36

Incarcerated

Answer 36

Stuck - irreducible Pain Sepsis Tissue breakdown

Question 37

Strangulated

Answer 37

Blood supply is disrupted and can lead to tissue necrosis