good

1. 32
Expert Review Examination of Groin Hernias
Laurence Toms*, Sam Mathew Lynn† and Ashok Handa#
……………………………………………………………………………………………………………………………………..
The Journal of Clinical Examination 2011 (11): 32-43
Abstract
Examination of groin hernias is an important skill for medical students and doctors. This article presents a
comprehensive, concise and evidence-based approach to examination of groin hernias which is consistent with
The Principles of Clinical Examination [1]. We describe the signs seen with groin hernias and, based on a review of
the literature, the precision and accuracy of these signs is discussed. Word Count: 2543 (excluding tables,
figures, references and abstract).
Key words: Hernia examination, Clinical examination, Inguinal hernia, Femoral hernia.
Address for correspondence: laurence.toms@doctors.net.uk
Author affiliations: * Final Year Medical Student, University of Oxford. † Final Year Medical Student, University of
Bristol. # Clinical Tutor in Surgery and Consultant Surgeon, University of Oxford and John Radcliffe Hospital,
Oxford.
……………………………………………………………………………………………………………………………………..
Introduction
A hernia is the protrusion of tissue through the wall
of the cavity in which it is normally contained.
Common types of abdominal and groin hernias are
listed in Table 1. This article describes the approach
to clinical examination of suspected groin hernias
(inguinal and femoral) in adults. It does not describe
the examination of other abdominal wall hernias.
The aim of the examination is to characterise the
lump and to make a diagnosis and differential
diagnosis. It is important to note that the differential
diagnosis includes pathologies which are not
hernias but maybe mistaken for them.
The relative frequencies of different types of hernia
are difficult to estimate and estimates are largely
based on registry data of operative management –
hence they underestimate those types of hernia that
are more often conservatively managed. See Table
1.
Background - Review of relevant anatomy
Inguinal hernias
The inguinal canal is a passage formed by the
aponeurosis of the external oblique, internal oblique
and transversalis fascia. The passage runs from the
deep inguinal ring (in the transversalis fascia) to the
superficial inguinal ring (in the external oblique
fascia). The inguinal canal contains the spermatic
cord (Figures 1 and 2) in men, which runs from the
abdominal cavity to the scrotum. In women, where
the canal is smaller, it contains the round ligament
of the uterus. The ilioinguinal nerve also runs
through the inguinal canal in both sexes.
The inguinal canal traditionally is thought of as
having four borders; inferior, superior, anterior and
posterior. The anatomy is shown in Figure 2. The
inferior border of the canal (often called the floor) is
the inguinal ligament (formed from the external
oblique aponeurosis). The anterior wall is mainly
formed by the external oblique aponeurosis, with
the lateral part reinforced by fibres of the internal
oblique. The medial end of the external oblique
aponeurosis forms the superficial ring. The posterior
wall is formed by the transversalis fascia): at the
lateral end of this is the deep inguinal ring and at
the medial end is the insertion of the conjoint
tendon, where the inferior borders of the
transversalis and internal oblique apnoneuroses
fuse and join to the pubis. The superior border
(often called the roof) is formed from this conjoint
tendon.

2. 33
Figure 1 Photographs taken during surgical
repair of a hernia showing the anterior view of
(a) the left spermatic cord within the inguinal
canal.
Figure 1 (b) the exposed spermatic cord
Figure 1 (c) The completed mesh repair just
prior to closure.
The deep inguinal ring and Hesselbach’s triangle
are weak points in the abdominal wall and are thus
predisposed to hernias. In an indirect inguinal
hernia, abdominal contents move through the deep
inguinal ring, down the inguinal canal to the
superficial ring and hence become extra abdominal.
A direct inguinal hernia moves directly through a
defect in the transversalis fascia and may or may
not pass through the superficial ring.
For the purposes of clinical examination it is
important to understand how surface anatomy
relates to this underlying anatomy. The inguinal
ligament runs from the pubic tubercle to the anterior
superior iliac spine (see Figure 3a and 3b). The
deep ring is immediately superior to the mid point of
this ligament (see Figure 4) and the superficial ring
is superio-medial to the junction of the ligament with
the pubic tubercle. The mid point of the inguinal
ligament should not be confused with the mid point
of the inguinal line (called the mid-inguinal point),
which runs from the pubic symphysis to the anterior
superior iliac spine. The mid-inguinal point marks
the femoral artery, which is medial to the deep ring.
The Inferior epigastric artery originates from the
femoral artery, which is important in defining the
borders of Hesselbach’s triangle.

3. 34
Figure 2 The anatomy of the right inguinal canal
showing (a) the bony pelvis with the inguinal
ligament
Figure 2 (b) the deep inguinal ring with the
external oblique muscle and aponeurosis
removed
Femoral hernias
A femoral hernia occurs when abdominal contents
pass through the femoral canal (see Figure 5). This
space, which usually only contains a few lymph
nodes, is the medial compartment of the femoral
sheath. The inguinal ligament is the superior border,
the femoral vein forms the lateral border, the
lacunar ligament forms the medial border and the
fascia over pectineus muscle forms the posterior
border. The neck of the femoral canal is narrow and
its medial border is particularly sharp-edged (formed
by the lacunar ligament), meaning that femoral
hernias are especially prone to irreducibility and
strangulation.
Figure 2 (c) the superficial ring with the external
oblique muscle and aponeurosis in place
An inguinal hernia always originates superior to the
inguinal canal at a variable point along its length
depending on whether the hernia is direct or
indirect. The end point of the inguinal canal is the
pubic tubercle, and a femoral hernia always
originates infero-medially to this. Hence if the point
of origin can be found, defining the surface anatomy
of the inguinal canal and the pubic tubercle are key
steps in differentiating these two types of hernia. It
is often stated that inguinal hernias originate
superior-medial to the pubic tubercle, as this is
where the superficial ring is. Whilst this is often the
case, inguinal hernias do not always exit via the
superficial ring, so this is not always true. However,
inguinal hernias always originate above the inguinal
ligament. Finding the public tubercle and inguinal
ligament is therefore the key step in clinical
examination of the groin.
Clinical presentation and management
Hernias usually present as a unilateral lump but
they may present with the symptoms of obstruction
or strangulation (for definitions of these terms see
Table 2). Complications of hernias are often medical
emergencies which are beyond the scope of this
article. Here we will focus on the non-emergency
presentation of a unilateral groin lump. This article
will focus on the examination of hernias which are
non-tender and non-obstructed at presentation. See

4. 35
Table 3 for descriptive terminology applied to
hernias.
Figure 3 (a) Schematic demonstrating the
difference between the midpoint of the inguinal
ligament and the mid-inguinal point.
Figure 3 (b) Identifying the right inguinal
ligament by palpating the pubic tubercle and the
anterior superior iliac spine.
Literature Search
We searched the literature with the ‘Diagnosis’
option of PubMed’s Clinical Queries feature, using
all appropriate MeSH terms (hernia; hernia, inguinal;
hernia, femoral; hernia, abdominal). We searched a
selection of standard European and American
textbooks, including specialised evidence-based
texts [3,4]. We also searched specific web based
resources [5,6] and relevant journals (Hernia and
Evidence Based Medicine) [7,8]. No clinical prediction
rules were identified.
Figure 4 Palpating the deep ring at the midpoint
of the left inguinal ligament
Examination
Preparation
Introduce yourself to the patient and confirm their
identity. Wash your hands and put on a pair of
gloves (gloves are not necessary but you may
prefer to wear them). The entire groin and waist
must be exposed for an adequate examination –
see Figure 6. This may cause embarrassment so try
to minimise the duration and the extent of exposure
of the genitalia. Allow the patient privacy to undress
and provide gowns and sheets if required. Ask the
patient to lie as flat as possible on an examination
couch with a pillow behind the head for comfort.
This positioning of the patient facilitates easy
inspection by ensuring that the groins are not
creased and also reduces intra-abdominal pressure
allowing reducibility/irreducibility of hernias to be
demonstrated. Ensure the patient is comfortable,
check they do not have any pain and take informed
consent.
Figure 5 The anatomy of the right femoral canal
Lying or Standing?

5. 36
There is no consensus in the literature on the
whether the patient should be examined standing,
supine or both. The supine position allows
subsequent examination of the abdomen and is
more comfortable for both the patient and the
examiner. Although a hernia will often be more
obvious in the standing position, a satisfactory
examination in the supine position will obviate the
need for standing examination. We therefore
recommend starting with the patient supine.
Figure 6 The correct positioning of the patient
for supine examination of a hernia. Note the use
of a towel to preserve patient dignity while
achieving adequate exposure.
Examination routine
Examination of a hernia has much overlap with the
generic Examination of Lumps and Bumps [9] and as
with all examinations proceeds in the following
sequence: inspection, palpation, auscultation
followed by special tests. It is often helpful to
compare the side with the suspected hernia to the
contralateral side because a ‘normal’ groin is difficult
to define and asymmetry is an important indicator of
unilateral pathology. However, beware that groin
hernias can be bilateral and so symmetry does not
necessarily mean that both sides are normal.
Inspection
Inspect the groin for lumps and look for scars in the
inguinal region from previous operations - see
Figure 7. Concentrate particularly on the area at the
medial end of the groin crease. Ask the patient to
cough (ask the patient to turn away first to avoid
them coughing on you) and then to lift their head off
the bed. These actions raise the intra-abdominal
pressure which may cause hernias to appear or
become more prominent. Try to make a judgement
about the site of the lump, its size, its shape, the
condition of the overlying skin, and whether or not it
appears to descend into the scrotum.
Figure 7 A healed incision from a previous open
inguinal hernia repair operation. The scar is now
barely visible and may easily be missed on first
inspection.
Palpation
You will already have an impression of the
characteristics of the lump from your inspection.
Confirm the site, size and shape of the lump as well
as the relationship of the lump to underlying
structures. As already explained, it is particularly
important to relate the site to the public tubercle and
the inguinal ligament. Try to define characteristics of
the surface and edge of the lump. Examine the
lump for consistency including fluctuance,
compressibility, pulsation and transillumination.
Table 4 summarises the key features of the
differential diagnoses.
If the lump descends into the scrotum it is
necessary to differentiate it from scrotal pathology
by attempting to ‘get above’ it. If the testes can be
felt separately, then the lump is unlikely to be
scrotal in origin. Please see The JCE Expert
Review: Examination of the male external genitalia
[10].
The cough test
The cough test should be performed during the
palpation section of the examination. The tips of the
examiner’s fingers should be placed over the lump.
The patient is then asked to cough (turning away
from the examiner to do this) - see Figure 8. If the
lump expands on raising the intra-abdominal
pressure in this way, the lump is said to be
expansile. This indicates that the pressure wave is
being transmitted through the abdominal wall to
increase the size of the lump, and therefore that a
hernia is likely. It is important to note that this is
different from a transmitted non-expansile cough
impulse, which is sometimes present in the absence
of a hernia.

6. 37
Figure 8 Performing the cough test. Here the
examiner is palpating a suspected inguinal
hernia.
Auscultation
Auscultate the hernia for bowel sounds with a
stethoscope. The interpretation of this test is
subjective, and it is generally considered to be of
low sensitivity and specificity, although there is little
evidence in this area. The presence of bowel
sounds confirms the presence of a bowel loop with
ongoing peristalsis. The absence of bowel sounds is
non-specific and requires more interpretation. The
most obvious explanation is that the hernia does not
contain a loop of bowel. However, bowel sounds will
also not be present in strangulated hernias because
of the failure of peristalsis.
Reduction
If a hernia is diagnosed then attempts should be
made to reduce it back into the abdominal cavity.
Should the hernia be very tender to palpation or
irreducible, urgent general surgery consultation is
required.
It is easiest to reduce groin hernias with the patient
lying flat in the supine position. Using both hands,
with the pulps of the fingers surrounding the neck of
the hernia, the proximal part should be guided by
slow gentle pressure through the fascial defect
aiming to move it from outside to inside the
abdominal cavity. If examination/manipulation of the
hernia at any stage is painful then the examination
should stop. In difficult cases a “Trendelenburg tilt”,
in which the patient is positioned supine at 20
degrees with their head down, may aid reduction.
Analgesia (to relax the abdominal wall musculature),
or a cold compress (to reduce oedema) can also be
used but should be allowed adequate time to work.
Excessive pressure on the apex of the hernia can
cause it to mushroom around the abdominal wall
defect, impeding reduction. Asking the patient to
reduce the hernia himself is an alternative and may
be less likely to cause pain. Successful reduction
may be accompanied by a ‘squelch’ (indicating that
the hernia contains bowel) and confirms the
diagnosis of a hernia. If it is not possible to reduce
the hernia then, by definition, this is an irreducible
hernia.
Once the hernia is reduced it is important to try to
differentiate between femoral and inguinal hernias
as the former are at higher risk of strangulation (see
Table 5). This is achieved by applying pressure over
the suspected origin of the hernia and then
increasing intra-abdominal pressure to see if the
hernia remains reduced.
Classically an inguinal hernia is said to lie above
and medial to the pubic tubercle, whereas a femoral
hernia lies lateral and below. However, as
discussed above, this is not always the case. To
identify a femoral hernia, Hair et al. suggest
applying pressure over the femoral canal. This can
be achieved either by following adductor longus
tendon to below the inguinal ligament and then
placing a finger anterior and lateral to the tendon, or
by palpating the femoral artery and placing a finger
approximately a finger breath medial to it. These
manoeuvres should obstruct the femoral canal and
hence a femoral hernia should remain reduced,
while an inguinal hernia will re-appear as an obvious
swelling when the patient is asked to cough[11].
Differentiating between direct and indirect inguinal
hernia has less clinical significance and current data
suggests that the accuracy of doing so is poor, EB2,
but none the less the question often arises in
medical finals and post-graduate examination and
candidates should use this opportunity to
demonstrate their understanding of the relevant
anatomy and pathology.
First, with the hernia reduced, locate and apply
pressure over the internal inguinal ring at the
midpoint of the inguinal ligament and ask the patient
to cough. If this manoeuvre prevents the hernia
reappearing, the hernia is said to be indirect. If this
fails, apply pressure over Hesselbach’s triangle and
ask the patient to cough. If this prevents
reappearance, the hernia is then said to be direct
(see Figure 9). If the hernia does not reappear, ask
the patient to stand and repeat both tests. Inguino-
scrotal hernias are almost always indirect. See
Table 6.

7. 38
Figure 9 Hesselbach’s triangle
Examination in the Standing Position
As previously noted there is no consensus on the
whether the patient should be examined standing,
supine or both. The routine above describes the
examination with the patient supine, however some
hernias spontaneously reduce in this position and
are only clinically detectable when the patient is
standing. The authors recommend starting the
examination with the patient in the supine position
but if no groin mass is identified, or examination is
inconclusive, then the examination should be
performed with the patient standing.
Ask the patient to stand, exposed below the waist.
Sit or crouch facing the patient with your eyes at
waist height. Inspect, palpate, auscultate and
attempt to reduce any mass as previously
described. The examination is technically more
difficult with the patient in the standing position, but
often makes the identification (but not reduction) of
hernias easier due to the effects of gravity.
Examination then proceeds in the same way as the
supine examination.
To Complete the Examination
In addition to the core examination described above
it may be necessary to examine the contralateral
groin for a hernia and also to examine the
abdomen. See The JCE Expert Review:
Examination of the Gastrointestinal System [17]. A
hernia on either side is a risk factor for a hernia on
the contralateral side so a thorough examination
should always include both groins. Examination of a
hernia may also reveal pathology in the abdomen
such as abdominal wall hernias or divarication of the
rectus muscles. In medical school and post-
graduate examinations you should indicate to the
examiner any additional examinations you would
like to perform and he may or may not ask you to
proceed.
Finally thank the patient, help them dress and wash
your hands.
Acknowledgements
Many thanks to Professor Paul Glasziou and Jo
Hunter for their advice with literature searches.
Thanks to Miss M Weisters for her help.
Conflicts of Interest
None declared

8. 39
References
[1] Jopling H, The principles of Clinical Examination.
The Journal Of Clinical Examination, 2006; 1: 3-6
[2] Henry M, T. J. Clinical Surgery. 2nd edition.
Saunders 2004
[3] Sapira. Sapira's Art and Science of Bedside
Diagnosis. 3rd edition. Lippincott Williams & Wilkins
2005
[4] McGee. Evidence Based Physical Diagnosis. 2nd
edition. Saunders 2007
[5] Clinical Evidence, BMJ ClinicalEvidence.com
[6] Up to Date, Wolters Kluwer UptoDate.com
[7] Hernia; The World Journal of Abdominal Wall
Surgery, Springer
http://www.springer.com/medicine/surgery/journal/1
0029
[8] Evidence Based Medicine, BMJ
http://ebm.bmj.com/
[9] Carey, J., Mortensen N. Examination of lumps
and bumps. The journal of Clinical Examination
2008; 6: 12-17
[10] Examination of the male external genitalia The
Journal of Clinical Examination 2011; 11: 22-31
[11] Hair A, Paterson & O’Dwyer Diagnosis of a
femoral hernia in the elective setting. Journal of the
Royal College of Surgeons Edinburgh (2001)
46:117-18
[12] Renzulli P, F. E., Schäfer M, Werlen S,
Wegmüller H, Krähenbühl L. (1997). Preoperative
Nyhus classification of inguinal hernias and type-
related individual hernia repair. A case for
diagnostic laparoscopy. Surg Laparosc Endosc.
7(5): 373-7
[13] Kraft BM, K. H., Kuckuk B, Haaga S, Leibl BJ,
Kraft K, Bittner R. Diagnosis and classification of
inguinal hernias. Surg Endosc; 2005; 17(12): 2021-
4
[14] Van den Berg JC, d. V. J., Go PM, Rosenbusch
G. Detection of groin hernia with physical
examination, ultrasound, and MRI compared with
laparoscopic findings. Invest Radiol (1999); 34(12):
739-43
[15] Novitsky YW, C. D., Kercher KW, Kaban GK,
Gallagher KA, Kelly JJ, Heniford BT, Litwin DE.
Advantages of laparoscopic transabdominal
preperitoneal herniorrhaphy in the evaluation and
management of inguinal hernias. Am J Surg 2007;
193(4): 466-70
[16] Black J, T. W., Burnand K, Browse N. Browse's
Introduction to the Symptoms and Signs of Surgical
Disease. 4th edition. Hodder Arnold 2005
[17] Gardner, A. Examination of the Gastrointestinal
System. The Journal of Clinical Examination 2006;
1:7-11

9. 40
Hernia type Description
Inguinal Caused by a weakness in the inguinal canal. Relative incidence 78%.
Femoral Caused by a weakness in the femoral canal. Relative incidence 7%.
Epigastric Caused by the weakness in the epigastric linea alba, between the umbilicus and the
xiphisternum. Relative incidence 1%.
Obturator Caused by the weakness in the obturator canal in the thigh. Mostly discovered at
laparotomy for strangulation.
Paraumbilical Caused by weakness around the umbilical scar in adults, displacing the umbilicus to
one side. High risk of obstruction and strangulation.
Incisional Caused by weakness in wounds after abdominal operations (relative incidence 3-
5%). Most often in mid–line vertical incisions. Risks factors are wound infection,
obesity and poor surgical technique. Strangulation is rare. Relative incidence 10%.
Spigelian Caused by a weakness in linea semiluminaris, at the lateral border of rectus
abdominis. High risk of strangulation.
Umbilical Only occurs in infants through the congenital weakness at the umbilicus. Most
spontaneously resolve. Relative incidence 3%.
Table 1: Types of abdominal and groin hernias [2]. Relative incidence is the incidence of each particular type of
hernia relative to all abdominal wall hernias.
Complication Definition
Irreducible The hernial contents cannot be returned to the bowel. This is either due to adhesions
or a narrow hernial neck.
Strangulated The blood supply to the contents of the hernia e.g. bowel or omentum is
compromised. Venous occlusion followed eventually by arterial occlusion results in
ischemia/infarction. This is a surgical emergency.
Obstructed The bowel lumen within the hernia sac becomes obstructed with typical clinical
features of pain, vomiting diarrhoea or constipation. This is a surgical emergency. If
the loop is closed, this will proceed to strangulation.
Table 2: The complications of abdominal and groin hernias.
Terminology Definition
Richter’s hernia The antimesenteric border of the bowel herniates through the abdominal wall defect.
Can result in strangulation and necrosis without obstruction.
Maydyl’s hernia Also called ‘hernia en W’, the ‘W’ shaped loop of bowel results in an intra-abdominal
segment (the middle of the loop), which is the strangulated segment
Pantaloon hernia Indirect and direct hernia are found together
Sliding hernia Part of the wall of the sac is formed by a viscus e.g. bladder or large bowel
Table 3: Special types of hernia.

10. 41
Differential Diagnosis of Groin Lumps Characteristics
Inguinal/femoral hernia See table 5
Saphena Varix Mass at the junction of the long-saphenous vein and femoral vein
(2cm infero-medial to the femoral artery) caused by an incompetent
valve. Expansile mass with a cough impulse and a thrill on distal
percussion. Often has a bluish tinge.
Ectopc/undescended testes Often a mass in the external ring. Underdeveloped hemi-scrotum.
Femoral artery aneurysm Expansile mass along the course of the femoral artery (runs through
mid point of the inguinal line).
Lymph node No cough impulse, non reducible, firm mass
Hydrocoele of the cord No cough impulse, fluctuates and transilluminates
Lipoma of the cord Soft mass, able to get above, does not transilluminate or fluctuate
Table 4: Differential diagnosis of a scrotal groin lump.
Femoral Inguinal
Reduces to a point infero-lateral to the pubic tubercle Reduces to a point superio-medial to the pubic
tubercle
Often irreducible Mostly reducible
Often presents with strangulation Mostly presents with asymptomatic mass
Small Can be large
Table 5: Distinguishing features of femoral and inguinal hernias.
Indirect Direct
Can descend into scrotum Does not descend into scrotum
Reduces upwards, laterally and backwards Reduces upwards, and straight backwards
Controlled by pressure over the internal ring Not controlled by pressure over the internal ring
Defect not palpable (behind fibres of external oblique) Defect may be palpable
After reduction, the bulge appears at the middle of the
inguinal canal then flows medially
After reduction, the bulge appears exactly where it was
before
Table 6: Distinguishing features of direct and indirect hernias. From The Symptoms and Signs of Surgical
Disease [16].

11. 42
Four studies [12-15] have looked at the accuracy (sensitivity and specificity) of clinical diagnosis of inguinal hernias.
The methods and results are summarised in the table below. None of these studies quantified kappa.
All four studies looked at populations of patients referred to hospital by general practitioners with a clinical
diagnosis of inguinal hernia. The majority of these patients had a unilateral hernia. However, some patients had
clinically evident bilateral hernias at presentation and were referred for management of both sides (for example,
Renuzulli et al [12] looked at 30 patients who were referred with 35 hernias i.e. 5 of the patients had bilateral
clinically evident disease).
The studies compared findings at clinical examination for both sides to those at laproscopic surgery for both
inguinal regions (in most cases this meant one clinically abnormal groin and one normal groin). The procedure
used was transabdominal preperitoneal laparoscopic repair. This procedure allowed an anatomical examination
from within the abdomen of both inguinal regions, even if only one groin was repaired. It was the gold standard for
accurate anatomical diagnosis of both groins.
This methodology as was used so that clinically normal groins could have a definitive anatomical diagnosis, and
hence the true negative and false negative rates of clinical examination could be collected (in addition to the true
positive/false positive rates at the clinically positive side). Hence examining both sides allowed both sensitivity and
specificity to be calculated. The results are shown in the table below.
Authors Ref Population n Incidence* Sensitivity Specificity
Renuzulli et al [12] 30 patients (with 35 suspected groin
hernias) referred for surgical
management of probable inguinal
hernia.
30 0.47 0.96 0.43
Kraft et al [13] 220 patients (with 274 suspected
groin hernias) referred for surgical
management of probable inguinal
hernia.
220 0.66 0.92 0.64
Van den Berg
et al
[14] 41 patients referred for surgical
management of clinically evident
inguinal hernias.
41 0.67 0.75 0.96
Novitsky et al [15] 262 patients (with 283 suspected
groin hernias) referred for surgical
management of probable inguinal
hernia.
262 0.54 0.95 0.80
*Incidence quoted is the total number of inguinal hernias found at surgery divided by the total number of groins
examined i.e. this is a measure of incidence per groin, whether clinically evident or not.
In summary, the sensitivity of clinical diagnosis of inguinal hernia is 0.75 - 0.96 and the specificity of clinical
diagnosis of inguinal hernias is 0.43 - 0.96. These are relatively wide ranges and more data is required to draw
confident conclusions but it suggests that clinical examination is relatively powerful for detecting and excluding the
presence of an inguinal hernia.
Evidence Box 1: Diagnosing Inguinal Hernias

12. 43
Two studies looked at the accuracy of differentiating direct from indirect hernias. In these studies the examining
clinician stated pre-operatively whether he/she thought the clinically evident inguinal hernia was direct or indirect.
This was compared with the findings at laparoscopic repair, which again provided a definitive clinical diagnosis.
The clinically normal side was not part of this analysis.
In one study [12], the sensitivity of detecting a direct inguinal hernia in a population of inguinal hernias was 0.71 and
the specificity was 0.57. In the other study [13], the ‘accuracy’ of differentiating direct from indirect hernias is given
as 0.54. The authors define ‘accuracy’ as the proportion of positive concurrences (i.e. the authors do not give the
data in the traditional sensitivity/specificity format, and do not provide the raw data for its calculation).
In summary, there are no high quality studies addressing this question, but the current data suggests that the
accuracy of differentiating direct from indirect hernias is poor. In medical finals and post-graduate examination
candidates are often asked to distinguish direct and indirect inguinal hernias by clinical examination. Candidates
should be aware that this examination is likely to have very little discriminating value but a proper explanation of
the traditional account allows them to demonstrate their understanding of the relevant anatomy and pathology.
Evidence Box 2: Differentiating Direct from Indirect Inguinal Hernias