Hernia indd

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Abdominal Wall Hernias: 
The Common and the Uncommon.
Dr Mark Sparnon, Dr Parineet Takhar, Dr Sarah Constantine, Dr Khimseng Tew
Queen Elizabeth Hospital, Woodville, South Australia
Introduction
Abdominal wall hernias are a common radiological finding, inci-
dentally detected in asymptomatic patients. The presence of a hernia 
is usually secondary to congenital abdominal wall defects and there 
is often an accompanying increase in the intra-abdominal compart-
ment pressure. Occasionally hernias can be complicated by incar-
ceration and strangulation with consequent bowel obstruction, bow-
el infarction and intense pain.
Several risk factors have been implicated in the development of her-
nias. They include obesity, pregnancy and perhaps most important-
ly, aging. Studies suggest aging contributes significantly to the break-
down of tissues resulting in the development of some groin hernias 
(1)
. The average life expectancy today is 78 years (Australian male)
(2)
and the incidence of direct inguinal hernias is 40%. In comparison, 
the incidence of direct inguinal hernias was 5% at beginning of the 
20th century, when life expectancy was 50 years 
(2)
.
The diagnosis of a hernia is usually made by clinical examination. 
However, in certain patients the diagnosis can be difficult (like those 
who are obese, in pain or have abdominal scarring). In such cases, 
medical imaging may be useful in guiding the clinician. Moreover, 
the presence of an abdominal wall hernia on imaging does not al-
ways correlate with the patient’s clinical presentation and may inad-
vertently divert the clinician away from the true pathology.
Anatomy
While the various techniques can accurately identify the presence 
of an abdominal wall hernia or fascia defect, knowledge of the rel-
evant anatomy is essential in determining the type of hernia. This 
information is also useful in predicting potential for complication. 
The inguinal ligament is important in differentiating femoral from 
inguinal hernias. The inferior epigastric vessels are a major land-
mark in determining whether an inguinal hernia is direct or indi-
rect. Knowledge of the posterior triangles of Grynfeltt and Petit is 
critical to lumbar hernias. Understanding of the muscle layers of the 
anterior abdominal wall is important to classifying ventral and para-
umbilical hernias.