The abdominal wall

Question 1

Define the terms reducible, irreducible, incarcerated, obstructed, strangulated and sliding with respect to the description of hernias

Answer 1

Reducible: The contents of the hernia can be completely replaced into the cavity Irreducible: The contents of the hernia cannot be completely replaced into the cavity Incarcerated: The contents of the hernia sac are stuck inside by adhesions Obstructed: Bowel contents cannot pass through the herniated bowel Strangulated: There is ischaemia of the contents of the hernia (due to obstructed venous return), which unless relieved will lead to gangrene and perforation Sliding: Sliding hernias are those in which part of the wall of the sac is formed by a viscus.

Question 2

Describe the anatomy of the inguinal canal. How does it form? Where is it? What does it contain?

Answer 2

The inguinal canal is formed by the relocation of the testes during the foetal development. It is about 4cm long and lies parallel and medial to the first part of the inguinal ligament. It contains: -3 arteries (testicular/ovarian, artery to the vas deferens, cremasteric artery) -3 nerves (genital branch of genitofemoral, ilioinguinal and sympathetic nerves) -3 other structures (the vas deferens/round ligament of the uterus, the pampiniform plexus and testicular lymphatics)

Question 3

Where are the superficial and deep rings of the inguinal canal located?

Answer 3

The deep inguinal ring is the entrance to the inguinal canal, located 1cm superior to the mid-point of the inguinal ligament (halfway from ASIS to pubic tubercle) The superfical inguinal ring is the exit of the inguinal canal, and this is found 1cm superior and lateral to the pubic tubercle

Question 4

Define indirect and direct inguinal hernia

Answer 4

Indirect (also known as congential inguinal hernia): Viscus traverses entire length of inguinal canal, entering at the deep ring and leaving at the superficial ring. The deep ring is lateral to the inferior epigastric vessels. (make up 2/3rd of inguinal hernias) Direct (also known as acquired inguinal hernia): Viscus breaks through weakness in the transversalis fascia, and passes through the superficial ring. The breach is commonly medial to the inferior epigastric vessels. (make up 1/3rd of inguinal hernias)

Question 5

List the factors that predispose to the development of inguinal hernia

Answer 5

Increased intra-abdominal pressure (chronic cough, heavy lifting, pregnancy, obesity, straining at micturition/defecation) and weakness of transversalis fascia (previous hernia, age) are two big factors influencing development of inguinal hernias.

Question 6

Describe the physical findings in patients with reducible inguinal herniae, including examination of the external ring and descent to the scrotum, and incarcerated inguinal herniae including the signs of bowel obstruction and possible strangulation

Answer 6

Asking the patient to cough, increasing intra-abdominal pressure, will lead to an impulse through the hernia. Reducing the hernia may allow for control at the deep inguinal ring if it is an indirect hernia (as it will pass through here). Scrotal continuation of a hernia is more common in indirect hernia but may occur in either. Incarceration will cause bowel obstruction, characterised by constipation, distension, vomiting, and pain. On examination there will be increased bowel sounds. Strangulation and ischaemia will be associated with the four signs of inflammation (pain, redness, swelling, warmth) and tenderness.

Question 7

What are the boundaries of the inguinal ligament?

Answer 7

MALT (2 Muscles, 2 aponeuroses, 2 ligaments, 2 ‘T’s Superior wall (2 muscles): Internal oblique & Transversalis abdominus Anterior wall (2 aponeuroses): Aponeurosis of external oblique & aponeurosis of internal oblique Inferior wall (2 ligaments): Inguinal ligament & lacunar ligament Posterior wall (2 T’s): Transversalis fascia and conjoint tendon

Question 8

Where do femoral hernias occurs? Where are they found?

Answer 8

Through the femoral canal. Femoral hernias are found laterally and inferiorly to the pubic tubercle (attachment of inguinal ligament).

Question 9

Describe the anatomy of the femoral triangle. How is it formed (What are its borders) ? What does it contain?

Answer 9

The femoral triangle is formed by the inguinal ligament superiorly, the medial border of sartorius laterally and the lateral border of adductor longus medially It contains the femoral nerve, femoral artery and femoral vein from lateral to medial. (NAVY - from lateral Nerve to ‘Y-fronts’ medially) Insert picture

Question 10

The femoral canal is the site of Where is the femoral canal? What does it contain?

Answer 10

The femoral canal lies at the medial extremity of the femoral sheath. The anterior border of the canal is the inguinal ligament, the medial border is the lacunar ligament and the lateral border is the femoral vein. The posterior border is the pectineal ligament. Insert pic It contains It contains the lymph node of Cloquet and fat

Question 11

Define Richter’s hernia

Answer 11

A hernia involving only one sidewall of the bowel and not the bowel lumen, which can result in bowel strangulation and perforation without causing obstruction or any of its warning signs. They are particularly likely in the femoral sac

Question 12

Describe the symptoms of patients with femoral hernia.

Answer 12

50% of patients will present as a surgical emergency due to obstructed contents, with the other presenting as a globular lump below and lateral tot the pubic tubercle. The femoral ring is tight, so strangulation is often occurs.

Question 13

Define a ‘True umbilical hernia’ Relate it to the embryological origin of the umbilicus

Answer 13

A true umbilical hernia is a defect in the anterior abdominal wall underlying the umbilicus, through which the intestine can protrude. Occurs in 3% of live births as a result of a defect in the transversalis fascia at the umbilical ring. It results from failure to completely close the umbilical cicatrix. It allows for herniation during periods of increased intra-abdominal pressure. http://www.bmj.com/content/347/bmj.f4252

Question 14

Define paraumbilical hernia. Cause?

Answer 14

An acquired hernia that occurs just above/below the umbilicus. They are caused by raised intra-abdominal pressure.

Question 15

What are risk factors for paraumbilical hernias?

Answer 15

They are caused by raised intra-abdominal pressure so are more common in obese, middle aged, multiparous (more than one child at birth e.g. twins) women.

Question 16

What is an exomphalos hernia?

Answer 16

Rare, failure of the gut (mid-gut) to return to the abdominal cavity following the embryological rotation that occurs outside of the body. The bowel is contained within a translucent sac which runs through the defective anterior abdominal wall. Requires urgent surgery

Question 17

What are the symptoms for a patient with true umbilical hernia? Reducible? Become obstructed?

Answer 17

Usually asymptomatic, more prominent on coughing/laughing but easily reducible. Very rarely become obstructed. 90% retract by the age of 2

Question 18

What are the symptoms for a patient with paraumbilical hernia? Reducible? Become obstructed?

Answer 18

They present with a localised dragging pain and enlarging hernia over time, often tender with colic from intermittent obstruction of the bowel. Mainly reducible, but due to the small neck they commonly strangulate/obstruct. Adhesions may develop.

Question 19

What are they signs that a hernia may be strangulated?

Answer 19

Findings supporting strangulation include redness, warmth, swelling, pain.

Question 20

How do incisonal hernias occur? What is the incidence of incisional hernias - how common and how often after surgery?

Answer 20

An incisional hernia occurs through a defect in the scar from previous abdominal surgery. It is most common with midline laparotomy scars. Incisional hernias make up 10% of the hernias seen and 1% of abdominal incisions are followed by hernias.

Question 21

What are the risk factors for incisional hernias?

Answer 21

Pre-operative factors: old age, poor nutrition (protein and Vitamin C deficiency), sepsis, uraemia, jaundice, obesity & steroids all decrease wound healing. During the operation: Vertical incision, knots that are too loose/too tight & presence of drains make hernias more likely. (poor technique, weak suture material) Post-operative factors: post operative ileus, coughing ,distension, wound infection, haematoma, obesity - anything that increases intra-abdominal pressure

Question 22

Describe the symptoms of incisional hernias

Answer 22

Many incisional hernias will be asymptomatic (though patients may present with a lump), watch for intestinal obstruction. Mostly asymptomatic although may be: -bulge in the scar and local discomfort -subacute bowel obstruction is common as the hernia enlarges There is a wide neck, so strangulation is generally uncommon, however as contents accumulate then adhesions often develop so the hernia becomes irreducible

Question 23

Describe the findings on physical examination of patients with ventral hernias including mass and tenderness in those with incarcerated hernias and estimation of the size of the defect in patients with reducible hernias

Answer 23

A midline ventral hernia may be seen as an elongated gap between the rectus muscles in elderly, wasted patients (divarication of the recti). The size of the defect may be estimated by reducing the hernia and then feeling for the borders.

Question 24

What are the common presenting features of epigastric herniae?

Answer 24

One or more small protrusions though the linea alba above the umbilicus, usually containing only extra peritoneal fat. Over 75% are asymptomatic, although some are very painful, with the pain worse on physical exertion or after meals

Question 25

What is divarication of the rectus abdominus muscle?

Answer 25

Divarication of the rectus muscle is where the rectus muscles do not meet in the midline at the linea alba, and thus spilt apart when the patient flexes the abdominal muscle. It is common but benign. (insert pic https://mutusystem.com/mutu-system-blog/diastasis-recti-test-what-works-and-what-to-avoid). Increased IAP will cause the left and right muscles to separate.

Question 26

How can you distinguish an epigastric hernia from a divarication of the rectus abdominus muscle

Answer 26

Epigastric hernias may occur anywhere between the xiphoid process and the umbilicus. Divarication of the rectus muscles occurs along the linea alba. When the patient does a sit-up, the rectus muscles are the only muscles being used and so a midline bulge and muscle separation will present in both epigastric hernia and divarication. When the patient coughs, all abdominal muscles are used, so the muscle separation and midline bulge will only occur in the hernia – the divarication is not as severe, as many muscle groups are being used – the rectus muscles are not taking all responsibility for the action and aren’t under maximum strain.