LUMPS AND BUMPS

IN THE GROIN

THE MEDICAL STUDENTS AND JUNIOR DOCTORS GUIDE TO

INGUINAL AND FEMORAL HERNIAS

VIKAS ACHARYA

FINAL YEAR MEDICAL STUDENT, PENINSULA MEDICAL SCHOOL

ACADEMIC YEAR 2010/2011

Contents Page

1 – Contents Page

2 – Introduction

3 – Surface anatomy of the Abdomen and Groin

4 – Anatomy of the Femoral Triangle and Femoral Sheath

5 – Femoral Hernias

6 – Anatomy of the Anterior Abdominal Wall and Groin

7 – Anatomy of the Inguinal Canal

8/9/10 – Inguinal Hernias (Direct/Indirect/Comparison Summary)

11 – Management of Hernias

12 – Differentials for lumps/bumps in the Groin

13 – Operation Hernia Charity Page

14 – Further Resources / References

Introduction

Being in the operating theatre can be a daunting experience, not only on your first encounter

but on each and every one! Consultants frequently ask medical students and junior doctors

questions which can sometimes catch us off guard. Surgeons are particularly reputable for

their quizzing of students and this booklet will hopefully give you a brief insight into the world

of femoral and inguinal hernias and the relevant anatomy surrounding them.

By discussing and presenting some basic anatomy, anatomical landmarks and the clinical

presentation of hernias, this booklet should hopefully help prepare you to answer some of

those questions which are frequently asked on ward rounds and in operating theatres. It is

important to understand that background reading is essential to help underpin basic science

to clinical scenario’s, this booklet cannot answer all the questions which will be asked but it

uses principles which can be applied to various specialties of surgery and clinical conditions.

Many types of hernias exist but only femoral and inguinal hernias are being explored in this

resource. The principles are similar but they do not necessarily have the same underlying

anatomy or clinical manifestations.

Should you have any questions or would like any further information on this resource please

do not hesitate to contact me.

Kindest Regards,

Vikas Acharya

vikas.acharya@doctors.org.uk

Definitions

*Hernia – The protrusion of an organ or tissue through the wall of a cavity in which it

normally lies.

It is important to note that a Hernia can have common complications. They may be, or may

later become, Incarcerated or Strangulated, these are of significant concern as they can

have a poorer prognosis:

*Incarceration – When the hernia is or has become irreducible, the hernia content cannot be

returned to their normal site by manipulation.

*Strangulation – When the hernia’s blood supply has become compromised, this can later

lead to necrosis.

*Sliding Hernia – When an organ is part of the hernia sac and moves with the hernia.

Surface anatomy of the Abdomen and Groin

The abdomen is the region of the body between the thorax and the pelvis, specifically

between the thoracic diaphragm (Bottom of the rib cage) and the pelvic brim at the pubic

symphysis.

It can be divided into 4 quadrants or 9 regions as displayed by the diagram below. These

regions are important on examination as pain/tenderness/guarding can indicate a problem in

that region. It is important to note that pain exists in three regions initially when visceral

peritoneum/organs are irritated, this is due to embryological development; the foregut

precipitates pain in the epigastric region, midgut in the umbilical region and the hindgut in the

hypogastric/suprapubic region.

The abdomen has a fibrous structure down the mid-line which is a fusion of the aponeuroses

of the abdominal muscles called the linea alba. Either side of it are the Rectus Abdominus

muscles, more commonly known as the “six-pack”. The umbilicus or “Belly-Button” is an

important anatomical landmark which is used as a reference point anatomically; its surface

marking is at L3/L4 and it is innervated by the T10 dermatome.

*Transpyloric Plane – A horizontal line mid-way between the suprasternal notch (Angle of

Louis) at T4 and the pubic symphysis.

*Subcostal Plane – A horizontal line at the costal margin (Tenth ribs), it is roughly an inch

above the umbilicus.

*Inter-Tubercular Plane - A horizontal line that passes through the elevated and rough iliac

tubercules of the pelvis (Located posteriorly).

*Groin - The crease at the junction of the inner part of the thigh with the trunk, together with

the adjacent region and often including the external genitalia.

It is important to know the anatomy of this region as hernias commonly occur here. They can

be in the upper part of the thigh (Femoral) or above/around the external genetalia (Direct

inguinal) or even into the scrotum (Indirect inguinal).

Anatomy of the Femoral Triangle and Femoral Sheath

Commonly asked and vital to know anatomical landmarks are the mid-inguinal point and the

mid-point of inguinal ligament. They are two positions very close to each other but have

different structures located deep to them making their positions important be able to

differentiate.

Mid-Inguinal Point is the point located half-way between the pubic symphysis and the

anterior superior iliac spine (ASIS) – the location of the Femoral Artery.

Mid-Point of Inguinal Ligament is the point located half-way between the pubic tubercle

and the anterior superior iliac spine (ASIS) – the location of the Deep Inguinal Ring.

The femoral triangle is an anatomical region located in the upper inner aspect of each thigh.

Its three borders are: inguinal ligament (Superiorly), adductor longus (Medially) and the

medial border of the sartorius (Laterally). A number of vital structures pass through here

including the deep inguinal lymph nodes, femoral vein, femoral artery and femoral nerve

(Medial to Lateral). A good mnemonic to remember this is VAN (Vein, Artery and Nerve).

The femoral sheath is a small compartmental funnel-shaped pouch which exists in the

femoral triangle. It is a downward prolongation of the transversalis and iliopsoas fascia. It

has three compartments; a lateral, intermediate and medial compartment which contain the

femoral artery, femoral vein and deep inguinal lymph nodes and fat respectively. The medial

compartment is also known as the femoral canal and at its proximal end has a ring like

structure called the femoral ring (Formed in the transversalis fascia). The femoral nerve exits

outside the femoral sheath, located lateral and posterior to the femoral sheath.

Femoral Hernias

A femoral hernia is a protrusion of peritoneum into the potential space of the femoral canal.

The sac may contain abdominal viscera, usually small bowel, extra-peritoneal fat or

omentum. Strangulation and Incarceration are common because femoral hernias tend to

have a narrow neck and have a smaller space (Femoral ring) in which to move out from.

They are roughly 4 times more common in women than in men but overall are less common

than inguinal hernias.

Femoral hernias are usually acquired. They can be pre-disposed to and caused by

increased intra-abdominal pressure such as in pregnancy, a chronic cough, gastrointestinal

obstruction or excessive straining such as lifting heavy weights or when there is weakness or

laxity of tissue, such as in Marfans syndrome.

Clinical Features:

Many femoral hernias are asymptomatic until incarceration or strangulation occurs. There

may be just an occasional dragging or aching sensation at the site. A small, firm, grape-like

lump can be felt below the inguinal ligament, lateral to its medial attachment to the pubic

tubercle – A lump Infero-Lateral to the Pubic Tubercule.

Compression of the femoral vein or long saphenous vein by the hernia within the sheath can lead to the subtle clinical sign of unilateral superficial venous dilatation.

A strangulated femoral hernia classically presents with colicky abdominal pain and signs of intestinal/bowel obstruction such as distension, vomiting and constipation. Often, local symptoms are absent and there is more discomfort in the abdominal region than in the femoral area meaning they can easily be missed if the anatomical regions where they exist are not examined. This is very common in elderly women.

Anatomy of the Anterior Abdominal Wall and Groin

The layers of the abdominal wall are commonly asked of students and junior doctors whilst

in theatre, knowing them can not only impress your consultant, but it can also allow you to

understand how and why a hernia exists and how to differentiate them. The embryology

behind how the layers are formed can help you appreciate the layers in the different

anatomical regions.

Please note: the table has been colour co-ordinated to highlight the structures which arise

from the same embryological origin, they then develop and move distally to form the

corresponding structures.

ABDOMINAL WALL SCROTUM AND AROUND TESTES

SKIN (Superficial) SCROTUM

SUB-CUTANEOUS FAT SUB-CUTANEOUS FAT

CAMPER’S FASCIA DARTOS FASCIA

SCARPA’S FASCIA DARTOS MUSCLE

EXTERNAL OBLIQUE MUSCLE EXTERNAL SPERMATIC FASCIA

INTERNAL OBLIQUE MUSCLE CREMASTER MUSCLE

FASCIA OF INTERNAL OBLIQUE CREMASTERIC FASCIA

TRANSVERSE ABDOMINAL MUSCLE INTERNAL SPERMATIC FASCIA

TRANSVERSALIS FASCIA --- THEN ONE OF ---

EXTRAPERITONEAL FAT PROCESSUS VAGINALIS (S. CORD)

PERITONEUM (Deep) TUNICA VAGINALIS (TESTES)

Anatomy of the Inguinal Canal

The Inguinal Canal is a cylindrical passage in the anterior abdominal wall which in men

conveys the spermatic cord and in women the round ligament. It is larger and more

prominent in men. It is an oblique canal which is roughly 4cm in length and is directed

anteriorly, inferiorly and medially from its origin.

Superficial inguinal ring – The exit of the inguinal canal

Deep inguinal ring – The entrance of the inguinal canal

It is also important to note that the inguinal ligament runs from the anterior superior iliac

spine (ASIS) to the Pubic Tubercle. It has importance as structures above/below it have

variations in their naming, such as the external iliac artery becoming the femoral artery at

this point of its course. The inguinal ligament is also used to describe surgical incisions.

Boundaries Structure

Anterior Wall External Oblique Aponeurosis

Posterior Wall Transversalis Fascia

Superior Border Conjoint Tendon

Inferior Border Inguinal Ligament

Roof Fibres of the Internal Oblique Muscle

Inguinal Hernias (Direct/Indirect/Comparison Summary)

An inguinal hernia is one of the commonest conditions treated by a general surgeon. Indirect hernias may occur at any age. They are common both in children and in the late teens or early twenties when work or sport may exacerbate a congenitally pre-disposed weakness. They are more common in males because the inguinal canal is wider than in females. About 60% occur on the right, 20% on the left, and 20% are bilateral.

An inguinal hernia is a protrusion of intra-abdominal tissue through the abdominal wall where it is weakened by the presence of the inguinal canal. In both, the sac usually contains omentum or small bowel, less commonly it can also contain large bowel, appendix or diseased tissue.

There are two main types of Inguinal Hernias:

Indirect (75%) - these originate lateral to the inferior epigastric artery and follow the path of the spermatic cord or round ligament through the deep inguinal ring and along the inguinal canal.

Direct (25%) - these originate medial to the inferior epigastric artery and push through a weakness in the posterior wall of the inguinal canal rather than down the canal itself.

Please note: The differentiation of a direct from indirect inguinal hernia is not vital as management is similar for both, however, for AMK and ward-round/theatre purposes it is useful to understand how both differ anatomically, clinically and on examination.

Indirect – Usually congenital, due to the failure of incorrect formation of the tunica vaginalis and therefore the deep inguinal ring is not closed properly.

Direct – Usually acquired, due to a weakness in the anterior abdominal wall and abdominal tissues/contents herniate through here.

Importance of the History

When taking the history of a man with a possible hernia, it is important to enquire about risk factors for herniation:

Occupation, particularly heavy manual work Chronic cough e.g. bronchitis Difficulty passing urine e.g. prostatic hypertrophy Constipation

These factors tend to increase the intra-abdominal pressure.

Inguinal Hernias - Clinical Features:

Inguinal Hernias may be diagnosed by a mass with a cough impulse in the inguinal region,

usually Supero-Medial to the Pubic Tubercle. They are rarely painful and the mass

commonly disappears on lying down. Irreducibility may indicate incarceration or the

presence of a sliding hernia. Local tenderness, warmth and pain over an irreducible mass

may indicate strangulation. If bowel herniates through the deep inguinal ring it may give

symptoms of bowel obstruction as discussed on page 5.

A direct inguinal hernia protrudes directly forwards when the patient stands up whereas the

indirect hernia shows a more oblique route through the inguinal canal downwards towards

the scrotum. A hernia which goes into the scrotum is therefore always Indirect.

A reduced indirect hernia can be controlled by applying pressure over the deep inguinal ring,

classically with a single finger, but a reduced, direct hernia cannot. This is a simple test you

can conduct on examination, ask the patient to reduce the hernia, apply pressure over the

deep inguinal ring and then ask them to cough, if it herniates, it must be a direct inguinal

hernia.

On standing, direct hernias appears immediately whilst the indirect hernia takes time to

reach its full size. Similarly, on lying down, direct hernias disappear immediately whilst there

is a delay before the reducible indirect hernia retracts fully.

This is due to the relatively large orifice of the direct hernia compared to that of the indirect

one. Due to the smaller orifice size of the deep inguinal ring, Indirect inguinal hernias are

more likely to strangulate than direct inguinal hernias.

Characteristic Features Direct (Acquired) Indirect (Congenital)

Pre-disposing factors

Weakness of anterior abdominal wall.

Improper formation of the Tunica Vaginalis (Patent

Processus Vaginalis).

Frequency Less common (Roughly 25% of Inguinal Hernias)

More common (Roughly 75% of Inguinal Hernias)

Exit from Abdominal Cavity

Peritoneum plus transversalis fascia (Lies outside the inner one or two fascial coverings of cord/round ligament).

Peritoenum of persistant processus vaginalis plus all three fascial coverings of cord/round ligament.

Anatomical Course

Through or around Inguinal Canal, usually

only traverses medial third of canal.

Traverses Inguinal Canal, usually entire canal if large

enough.

Exit from Anterior Abdominal Wall

Via Superficial Inguinal Ring, lateral to the

cord/round ligament and rarely enters Scrotum.

Via Superficial Inguinal Ring, inside the cord and commonly passes into the Scrotum or Labium Majus.

Management of Hernias

All groin hernias should be surgically repaired unless there are specific contraindications.

For indirect hernias, this is because the complications of incarceration, obstruction and

strangulation are greater than those of operation. Direct hernias do not carry the same risks

but the difficulty in reliably differentiating them from indirect hernias makes repair advisable.

Femoral hernias including asymptomatic ones must be surgically repaired without delay

because of the risk of strangulation of abdominal contents in the canal. Both types are

usually repaired electively, if complications exist such as obstruction then emergency

surgery may be necessary. In all, mesh prosthesis is used as reinforcement in order to

reduce the risk of recurrence.

There are several operative approaches for a Femoral Hernia repair:

Abdominal or Extraperitoneal approach Inguinal or 'high' approach Crural or 'low' approach Transperitoneal approach Laparoscopic approach

A Herniorrhaphy generally refers to the operation for repair of an indirect or direct inguinal hernia, although it should apply to any hernia repair. It can be performed by an open or laparoscopic technique.

A Herniotomy operation is performed on infants to repair an inguinal hernia. The patent processus vaginalis is ligated and excised. It is generally unnecessary for a formal repair of the abdominal wall to be performed.

None of these suffices for all circumstances, but all have the aim of:

Reduction or excision of the hernial sac Reinforcement of the femoral canal / deep inguinal ring (If applicable)

Contraindications to surgery

Extremes of age General debility Large direct hernia that is easily reduced and the

patient elects to use a Truss

A Truss may be used to 'control' certain types of hernias. This may be indicated when surgery is inappropriate or unacceptable to the patient. They work by applying pressure to a hernia to prevent it from protruding, e.g. padded webbing attached to a belt to compress the inguinal canal from front to back, thus preventing the protrusion of an inguinal hernia. They can be safely used so long as the hernia is reducible, and can be kept reduced and free of symptoms.

Differential Diagnoses for lumps/bumps in the Groin

Patients may feel embarrassed when they see you regarding their presenting complaint, it is

important that you allow them to tell their story and maintain their dignity during your

examination. It is vital to accurately take a history and think about the differentials for their

complaint.

Benign conditions are common but it is important to consider more sinister causes of the

groin swelling(s) so as not to miss them in primary care or in hospital. Knowing the anatomy

of underlying structures assists in understanding the pathology that can develop. Taking

family history, age, lifestyle and risk factors into consideration with a good examination can

help form a solid list of differentials.

Inguinal Hernia

Femoral Hernia

Lymphadenopathy – Inguinal Lymph Nodes

Cyst of canal of Nuck

Saphena Varix (Varices of the Saphenous Vein)

Varicocoele

Psoas Sheath: Psoas Bursa or Psoas Abscess

Femoral Artery: Femoral Artery Aneurysm

Testicular apparatus: Hydrocoele of the Spermatic Cord, Ectopic Testis

Skin and subcutaneous tissues: Lipoma, Infection, Abscess

Testicular Carcinoma (Various types of tumours may exist)

Knowing the list is only useful if one understands what they are and how they may or may

not present. This can then be combined with the information extracted from a history to give

you more of an idea of the likely cause of this groin swelling. This list is only a starting point

for you to go away and research pathological causes for swellings in the groin.

Operation Hernia Charity Page

In Africa, Hernias are not routinely treated due to a lack of hospitals and surgeons. There are

ten times more patients in Ghana with Hernias compared to an equivalent population in

Europe. In rural Africa, it has been estimated that less than 1 in 5 inguinal hernias requiring

surgery actually receive an operation. Few patients with neglected hernias that strangulate

may not even reach a hospital, and die needlessly. In rural areas of Africa basic surgical

services are not available and there is no possibility that Governments will be able to provide

such facilities in the near future.

The organisation is an independent UK charity and non-profit organisation which has

expanded its mission into low-income countries of South America. Professor Kingsnorth and

Mr Oppong are both consultants in Derriford Hospital, Plymouth.

Operation Hernia is a surgical programme intended to treat and teach groin hernia surgery in

Africa and other low-income countries. It was initiated in 2005 in Takoradi, Western Ghana.

Surgeon Volunteers are drawn mainly from members of the European and American Hernia

Societies. Professor Andrew Kingsnorth recruits Volunteers, initiates and organises the

missions, with the assistance of Mr Chris Oppong (Project Director, Takoradi) and Dr

Charles Filipi (Project Director, Western Hemisphere).

For more information on this project and to get involved, please visit their website:

www.operationhernia.org.uk

Further Resources / References

1. Moore & Dalley, Clinically Oriented Anatomy

2. Netter, Netters Clinical Anatomy

3. Netter, Netters Anatomy

4. GP Notebook

5. Whittaker R, Instant Anatomy

6. NHS Direct, www.nhs.uk/conditions/hernia

7. Operation Hernia Website, www.operationhernia.org.uk

8. Oxford Handbook of Clinical Medicine, Seventh Edition

9. Oxford Handbook of Clinical Surgery, Second Edition

Acknowledgements

I would like to take this opportunity to thank the following people for assisting and guiding me

throughout this learning booklet construction:

Mr Chris Oppong, Consultant Surgeon at Derriford Hospital in Plymouth for proof-reading

this learning resource and providing learning opportunities and guidance on my general

surgery attachment.

Mr Chris Challand and Mr Duncan Cundall-Curry for proof reading this learning resource.

I would like to also thank all medical students and junior doctors who assisting in the

research and development of this learning resource.

Should you have any questions or would like any further information on

this resource please do not hesitate to contact me.

Best wishes for your studies and beyond.

Vikas Acharya

vikas.acharya@doctors.org.uk