Inguinal Hernia

Inguinal Hernia


Overview Higher incidence among men 40 to 59 years of age. Although there are many different types of hernias, they are usually related to the abdomen, with approximately 75% of all hernias occurring in the inguinal region. Hernia contains omentum (90% of cases) or intestine (10% of cases). Inguinal hernias are at risk of irreducibility or incarceration, which may result in strangulation and obstruction. However, femoral hernias are much more likely to strangulate compared to inguinal because of the narrowed femoral ring.

A bulge or protrusion of an organ or tissue through an abnormal opening within the anatomic structure that normally confines it.
Inguinal Hernia:
Reducible:  Refers to a hernia that can be moved back into place easily (either manually or spontaneously)
Irreducible: Refers to a hernia that CANNOT be moved back into place, remains budged. Irreducible hernia can lead to a incarcerated, obstructed or strangulated hernia.
Incarcerated:  Refers to a hernia that cannot be pushed back.  It does not necessarily mean that the hernia is strangulated or that obstruction is occurring (although both are possible).  If spontaneously reduced, and patient feels better.
Obstructed hernia:
gut hernia causing incarceration (momentum hernia does not cause incarceration because gut flow is normal)
Strangulated hernia: compression of blood flow to the strangulated bowel leading to necrosis
Side note The composition of a hernia is 1. the sac, 2. the covering of the sac 3. the content of the sac

Anatomy of the Abdominal Wall

"No disease of the human body, belonging to the province of the surgeon, requires in its treatment a better combination of accurate anatomical knowledge with surgical skill than Hernia in all its varieties" Astley Cooper (1804)

Inguinal Hernia Anatomy

The inguinal canal is the oblique passage through the lower abdominal wall. It runs from deep to superficial, from internal to external inguinal rings. The testis follows this canal and into the scrotum during development, and therefore the spermatic cord runs through this canal.

  • Superficial (external) inguinal ring is a V-shaped defect in the external oblique aponeurosis.
  • Deep (internal) inguinal ring is formed through the transversalis fascia. It is located above the mid point of the inguinal ligament.

The deep and superficial ring should close normally

Mid-inguinal point (between the ASIS and pubic symphysis): Femoral artery
Mid point of the inguinal point (between the ASIS and pubic tubercle): deep ring of the inguinal canal

Borders of the Inguinal Canal

  • Posterior (deep ring): Transversalis fascia
  • Anterior (superficial ring): External oblique aponeurosis (not muscle)
  • Floor: Inguinal ligament
  • Roof: (conjoint tendon?)/Transversalis Fascia, Internal oblique

Contents of the Inguinal Canal (rule of 3s)

  • Artery: Cremastric, testicular, vas deferens
  • Others: Spermatic cord (vas deferens), Pampinform plexus, lymphatics
  • Nerve: Genital branch of the genitofemoral nerve, sympathetic nerve, ilioinguinal nerve
  • Layers: (Processus vaginalis) + Internal spermatic fascia, cremastic muscle, external spermatic fascia
Remember in females the content of the inguinal canal is four things: Round ligament, genital branch of the genitofemoral nerve, lymphatics and sympathetic plexus

Borders of the Hesselbach Triangle

  • Inferiorly: Inguinal ligament (Iliopubic tract labroscopically)
  • Laterally: Inferior epigastric artery
  • Medially: lateral border of rectus muscle

Types of Inguinal Hernia

  Indirect Inguinal Direct Inguinal Femoral
Definition Intestine passes through deep inguinal ring Intestine passes through weak abdominal wall Intestine passes through weak femoral ring
Age Any age but usually young Acquired weakness in abdominal wall More common in women, due to their wider bony pelvis
Aetiology Congenital (patent process vaginalis) Acquired Acquired
Relationship to inferior epigastric artery Lateral Medial An aberrant obturator artery of  the inferior epigastric  arery ,ay cross the lacunar ligament
Descending to scrotum Often Rarely -
Occluding the internal ring Controls it Does not control it -
Neck Narrow Wide Narrow
Strangulation More likely Rare Much more likely
Treatment Infant - herniotomy, Adults - open/laparoscopic mesh Open/laparoscopic mesh Laparoscopic mesh


Risk Factors

  • Family history
  • Personal history
  • Smoking
  • Increasing age — the lifetime risk of a man aged 25 developing an inguinal hernia is one in five. At age 65 it is two in five
  • Systemic disease processes such as cirrhosis, renal failure, scurvy or malnutrition
  • Raised intra-abdominal pressure, such as occurs with pregnancy, ascites or obesity
  • Straining, such as chronic cough, prostatism or chronic constipation.



Signs and Symptoms

The diagnosis of an inguinal hernia is usually made through history and physical examination findings. Patients can either be asymptomatic or symptomatic

Asymptomatic with a bulge

Symptomatic with a buldge- Gradually or suddenly

  • Groin pain
  • Burning
  • Gurgling
  • Aching sensation in the groin
  • Heavy or dragging sensation may worsen toward the end of the day and after prolonged activity.
  • An abdominal bulge may disappear when the patient is in the prone position


  • Examine the patient first when he or she is standing
  • Demonstrate lump with:
    • Valsalva maneuvers → may worsen pain
    • Cough impulse → cause more abdominal contents to be pushed through the hernia defect → larger hernia
  • Then do an abdominal examination with the patient lying down
  • No merit in trying to differentiate between direct and indirect hernias
  • Remember differential diagnosis
Remember Hernias may be easily diagnosed with an adequate physical examination
Side note Bilateral inguinal hernias are extremely common, as is clinically evident connective tissue weakness in both groins. Any patient presenting with an inguinal hernia should have the contralateral groin examined when lying flat.
Red Flag Triad: Irreducible, Absent cough impulse, Pain

Differential Diagnosis

Condition Clinical features
Ectopic testis Absence of a testis in the scrotum
Epididymitis Severe pain surrounding the testis, tenderness, fever, chills
Femoral adenitis/adenopathy Bilateral, firm, tender nodes; fever
Femoral arterial aneurysm Older patient, pulsatile mass, no systemic symptoms
Femoral hernia More common in women, often incarcerated, bowel obstruction
Hematoma Associated trauma, ecchymoses, tenderness, no change with Valsalva maneuver
Hidradenitis Draining abscesses in intertriginous skin of the groin
Hydrocele Mass in the scrotum or inguinal canal that transilluminates
Inguinal adenitis/adenopathy Tenderness, redness possible, often bilateral, systemic symptoms
Inguinal hernia Bulge or impulse detected in inguinal canal with Valsalva maneuver or coughing
Lymphoma Firm, tender mass; may increase in size; organomegaly; systemic symptoms
Lipoma Soft, asymptomatic mass; does not change in size


  • Hernia is a clinical diagnosis and should be referred to a surgeon. Ultrasound does not change management and so is unnecessary.
  • The surgeon can order imaging if necessary prior to surgery when the diagnosis is uncertain


Hernia occur at sites of weakness in the wall. This weakness may be:

  • Normal (physiological weakness, related to the anatomical causes - due to increased intrabdominal pressure
  • Congenital abnormality
  • Acquired - either traumatic and diseased

In terms of inguinal herniae:

  • Neonatal and infantile inguinal hernia - Pathological failure of obliteration of the embryological processus vaginalis at birth
  • Adult inguinal hernia - pathological change in collagen. A wide body of evidence continues to accumulate regarding defective collagen as the main factor.


Non-Surgical Treatment

  • Watchful waiting, althought surgery is advised incase of future complications associated with hernia such as strangulation or incarceration

Surgical Treatment (recommended)

  • Open or larproscopic - depending on clinical situation and patient comorbidity
  • Mesh or suture repair - mesh better prognostically
  • Local or general anaesthetics
Advantages Disadvantages
Quicker recovery time than open repair — usually about half the time to activity. Rarely, unrecognised bowel perforation caused by balloon inflation has occurred when dense adhesions after peritonitis have tethered the bowel
Less postoperative pain has been shown in several series More expensive than open repair
Less chronic groin pain — the surgery takes place behind the muscles, so no nerves are likely to be damaged Future prostate cancer surgery is very difficult for the urologist, as the pre-peritoneal space anterior to the bladder is obliterated
Less risk of damage to the testicular blood supply A general anaesthetic is always required



Complication of hernia

  • Strangulation
  • Incarceration
  • Obstruction

Complication of Surgery

  • Early - Death, wound infection, Haemotoma
  • Late - Hernia reoccurrence, Chronic pain from nerve injury


Jenkins, JT 2008, Inguinal hernias, BMJ, vol. 336, no. 7638, pp. 269-272.
Phillips, DJ 2006, How to Treat, Australian Doctor.