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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Most common hernia (~75% of all hernias). Males predominate (lifetime risk: males ~27%, females ~3%)
- Indirect (60%): through deep inguinal ring, lateral to inferior epigastric vessels. Follows the inguinal canal. Commoner in young males
- Direct (40%): through posterior wall (Hesselbach triangle), medial to inferior epigastric vessels. Older males with weak abdominal wall
- Key examination: cough impulse, reducibility, relationship to pubic tubercle (inguinal = above and medial; femoral = below and lateral)
- Treatment: elective mesh repair (Lichtenstein or laparoscopic TEP/TAPP). Urgent surgery if incarcerated/strangulated
Overview
Inguinal hernias are protrusions of peritoneum ± abdominal contents (omentum, bowel) through the inguinal canal. Indirect inguinal hernias pass through the deep (internal) inguinal ring and are lateral to the inferior epigastric vessels — they follow the path of the inguinal canal and may descend into the scrotum. They are caused by a patent processus vaginalis (congenital) or weakness at the deep ring. Direct inguinal hernias protrude through the posterior wall of the inguinal canal (Hesselbach triangle), medial to the inferior epigastric vessels — these are acquired, caused by weakened transversalis fascia, and are more common in older men.
Epidemiology
Inguinal hernias account for approximately 75% of all abdominal wall hernias. Lifetime risk in males is ~27%, in females ~3%. Approximately 70,000 inguinal hernia repairs are performed annually in the UK. Indirect hernias are more common overall (60%) and predominate in younger patients and children. Direct hernias are more common in older males. Risk factors include male sex, increasing age, chronic cough, constipation, heavy lifting, previous hernia repair (recurrence), connective tissue disorders, and obesity.
Clinical Features
Symptoms
Lump in the groin that appears on standing/straining and disappears on lying down (reducible)
Aching or dragging discomfort in the groin (worse at end of day, on standing, or with exertion)
Lump may extend into scrotum (indirect hernia)
Irreducible lump + pain + vomiting (incarceration progressing to strangulation)
Signs
Visible and palpable groin lump above and medial to pubic tubercle
Cough impulse present (expansile impulse on coughing)
Reducible (contents can be pushed back into abdomen) — many can be reduced
Indirect: controlled by pressure over deep ring (midpoint of inguinal ligament). Can descend into scrotum
Direct: NOT controlled by deep ring pressure. Does NOT descend into scrotum. Bulges forward on coughing
Irreducible, tender, erythematous, absent cough impulse (strangulation)
Investigations
First-line
Clinical diagnosisInguinal hernias are diagnosed clinically in most cases — imaging not routinely required
Second-line
UltrasoundIf diagnostic uncertainty (e.g. obese patient, recurrent hernia, intermittent swelling) — can confirm hernia and differentiate from lymphadenopathy, lipoma, or saphena varix
CT abdomen/pelvisIf suspected incarceration/obstruction with signs of bowel obstruction
Specialist
MRIRarely needed — for complex recurrent hernias or occult hernias causing groin pain
1
Asymptomatic/minimally symptomatic
- Watchful waiting is an option for minimally symptomatic inguinal hernias (particularly direct) — low risk of strangulation (~0.3–3% per year)
- Patient should be counselled on warning signs of strangulation and when to present urgently
2
Elective repair (symptomatic)
- Open Lichtenstein repair: tension-free mesh repair under local/general anaesthesia — gold standard for primary inguinal hernia
- Laparoscopic repair (TEP or TAPP): suitable for bilateral hernias, recurrent hernias, or patient preference. Faster recovery, less chronic pain
- Day-case surgery in most patients
- Mesh use reduces recurrence from ~15% (suture) to <2% (mesh)
3
Emergency (incarcerated/strangulated)
- Attempt gentle reduction (with adequate analgesia and positioning — Trendelenburg, ice) only if no signs of strangulation
- If irreducible, tender, or signs of obstruction: emergency surgical exploration
- Assess bowel viability at operation — resect if non-viable
- Strangulated hernia is a surgical emergency — mortality increases with delay
Complications
- Incarceration: Contents trapped and cannot be reduced — risk of progression to strangulation
- Strangulation: Vascular compromise of herniated contents (usually bowel) → ischaemia → gangrene → perforation. Surgical emergency
- Bowel obstruction: Incarcerated bowel causes mechanical SBO
- Post-operative: Chronic groin pain (~10%), wound infection, haematoma/seroma, recurrence (~2% with mesh), mesh infection (rare)
UKMLA Exam Tips
- 1Inguinal hernia: above and medial to pubic tubercle. Femoral hernia: below and lateral to pubic tubercle
- 2Indirect = through deep ring = LATERAL to inferior epigastric vessels. Direct = MEDIAL to inferior epigastric vessels
- 3Indirect hernias can descend into the scrotum; direct hernias do NOT (usually)
- 4You can get above an inguinal hernia but NOT a scrotal swelling (testicular pathology) — key clinical distinction
- 5Strangulated hernia: irreducible + tender + erythematous + absent cough impulse ± signs of obstruction → emergency surgery
- 6In children, inguinal hernias are virtually always INDIRECT and require surgical repair (they do not resolve spontaneously)
practicetest your knowledge on inguinal herniaApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — gastroenterology and beyond.
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