Surgery :Hernias and the abdominal wall

• Basics: What Is a Hernia? | Anatomy of the Groin | Examining a Groin Lump
• Types of hernia: Inguinal Hernias | Femoral Hernias | Umbilical, Paraumbilical and Epigastric Hernias | Incisional and Parastomal Hernias | Rarer Hernias | Hiatus and Diaphragmatic Hernias
• Complications and treatment: Incarceration, Obstruction and Strangulation | Hernia Repair | Complications of Repair and Recovery
• Other abdominal wall problems: Divarication, Haematoma and Abdominal Wall Lumps | Hernias in Children
• Revision: Groin and Abdominal Wall Lumps at a Glance | Spot the Diagnosis | Exam-style Scenarios | Key Points | Guidelines and Further Reading

🩹 Hernias and the abdominal wall — page 3 of the Surgery chapter. Hernias are among the commonest reasons for surgery. Most are harmless bulges, but a hernia that becomes painful, tender and irreducible can strangulate — cutting off the blood supply to bowel — and needs emergency surgery. Femoral hernias in older women are the classic dangerous ones. Always examine the hernial orifices in anyone with bowel obstruction.
Your four questions for every patient: Is this a hernia, and which type? Is it reducible, or is it incarcerated, obstructed or strangulated? Does it need surgery — routinely, urgently or as an emergency? Is the patient fit, and what are their wishes and risk factors (smoking, obesity, cough, constipation)?

What Is a Hernia?

• A hernia — part of an organ or tissue (usually bowel or fat) pushes through a weakness in the wall of the cavity that normally contains it.
• Terms:
  • Reducible — goes back in (by itself when lying down, or with gentle pressure).
  • Irreducible (incarcerated) — can't be pushed back, but the blood supply is intact.
  • Obstructed — bowel trapped in the hernia is blocked → bowel obstruction.
  • Strangulated — the blood supply to the trapped tissue is cut off → ischaemia and gangrene within hours — emergency.
  • Richter's hernia — only part of the bowel wall is trapped — it can strangulate without causing obstruction (easily missed).
  • Sliding hernia — part of the hernia sac wall is formed by an organ (e.g. bladder or caecum).
• Risk factors — conditions that raise abdominal pressure (chronic cough, constipation, straining to pass urine — prostate enlargement, heavy lifting, obesity, pregnancy, ascites, peritoneal dialysis) and those that weaken the wall (age, previous surgery, wound infection, smoking, steroids, connective tissue disorders, male sex for inguinal hernias).
• Symptoms — a lump that appears on standing, coughing or straining and goes away when lying down; aching or dragging discomfort; sometimes none.

Anatomy of the Groin

• Inguinal canal — an oblique passage about 4 cm long above the medial half of the inguinal ligament, carrying the spermatic cord in men (the round ligament in women) and the ilioinguinal nerve.
• Deep (internal) ring — a hole in the transversalis fascia, about 1–1.5 cm above the midpoint of the inguinal ligament, just lateral to the inferior epigastric vessels.
• Superficial (external) ring — a gap in the external oblique aponeurosis, above and medial to the pubic tubercle.
• Walls ("MALT") — roof: Muscles (internal oblique and transversus); anterior: Aponeurosis of external oblique; floor: inguinal Ligament; posterior: Transversalis fascia (and conjoint tendon medially).
• Hesselbach's triangle — bounded by the inferior epigastric vessels (lateral), the edge of rectus abdominis (medial) and the inguinal ligament (below) — the site of direct inguinal hernias.
• Femoral canal — below the inguinal ligament, medial to the femoral vein (from lateral to medial: Nerve, Artery, Vein, Empty space, Lymphatics — "NAVEL"); its narrow, rigid neck explains why femoral hernias strangulate.
• Landmarks — the pubic tubercle is the key: inguinal hernias appear above and medial to it; femoral hernias below and lateral to it.

Examining a Groin Lump

• Examine standing and lying, both sides, with the patient's consent and a chaperone; expose from the umbilicus to the upper thighs, including the scrotum.
• Inspect — site, size, shape, skin changes, scars; ask the patient to cough and watch for a bulge.
• Palpate — tenderness, temperature, consistency, cough impulse, reducibility (ask the patient to reduce it, or reduce gently lying down), relationship to the pubic tubercle.
• Scrotal lumps — can you get above it? If not, it is coming from the groin (an inguinoscrotal hernia); if you can, it arises in the scrotum (hydrocele, cyst, testicular mass — see the Urology page).
• Deep ring occlusion test — pressing over the deep ring after reduction; if the hernia doesn't reappear on coughing, it suggests an indirect hernia — but this is unreliable at distinguishing direct from indirect (the surgeon confirms at operation).
• Also check — the other side, abdomen (masses, ascites, scars), causes of raised pressure (cough, constipation, prostate symptoms), and the testes.
• Imaging — usually not needed; ultrasound if the diagnosis is unclear (small or occult hernias, groin pain); CT in obstruction or for complex abdominal wall hernias.

Inguinal Hernias

• The commonest hernia — much more common in men (lifetime risk about 1 in 4 men); can occur at any age.
• Indirect inguinal hernia:
  • Passes through the deep ring, lateral to the inferior epigastric vessels, along the canal, and can descend into the scrotum.
  • Caused by a persistent processus vaginalis (a congenital sac) — the type seen in children and young men.
  • More likely to become incarcerated than direct hernias.
• Direct inguinal hernia:
  • Bulges through the weak posterior wall (Hesselbach's triangle), medial to the inferior epigastric vessels.
  • An acquired weakness in older men; a wide neck — rarely strangulates; seldom enters the scrotum.
• Management:
  • Symptomatic hernias — offer repair (usually day case).
  • Minimal or no symptoms in men — watchful waiting is reasonable (low risk of complications), but many eventually develop symptoms and choose repair.
  • Women — repair because of the risk of a femoral hernia being mistaken for an inguinal one (laparoscopic repair covers both).
  • Children — repair soon after diagnosis (herniotomy), urgently in infants (high risk of incarceration).
• Reduce risk factors — stop smoking, treat chronic cough and constipation, investigate prostate symptoms, weight loss.

Femoral Hernias

• Through the femoral canal, below the inguinal ligament, below and lateral to the pubic tubercle, medial to the femoral vein.
• Who — more common in women (wider pelvis), especially older, thin women; but inguinal hernias are still more common in women overall.
• Features — a small, firm lump in the upper medial thigh; often irreducible and with no cough impulse; frequently presents with bowel obstruction (sometimes the lump is overlooked, especially in obese patients) or as a Richter's hernia.
• High risk of strangulation — the neck is narrow and rigid — so all femoral hernias should be repaired promptly (urgently if symptomatic), and an obstructed or strangulated femoral hernia needs emergency surgery.
• Differential — inguinal hernia, saphena varix (soft, bluish, disappears on lying down, cough thrill, varicose veins), enlarged lymph node, femoral artery aneurysm (pulsatile), psoas abscess, lipoma.

⚠️ Safety Pearl: In an older woman with small bowel obstruction and no previous surgery, look carefully for a small femoral hernia — it is easily missed, especially in obesity, and strangulates readily.

Umbilical, Paraumbilical and Epigastric Hernias

• Umbilical hernia in infants — through the umbilical ring; common (especially in premature babies and children of Black African or Caribbean family origin); soft, reducible, rarely complicated; most close by about 4–5 years — repair if persisting beyond that or very large.
• Paraumbilical hernia in adults — through the linea alba just above or below the umbilicus; risk factors — obesity, multiple pregnancies, ascites, previous laparoscopic port; narrow neck — risk of incarceration and strangulation; repair (often with mesh) if symptomatic.
• Umbilical hernias in cirrhosis with ascites — can ulcerate and rupture (leaking ascitic fluid — emergency); treat the ascites; repair is higher risk (specialist decision).
• Epigastric hernia — small defects in the linea alba between the umbilicus and xiphisternum, usually containing fat; can be painful; repair if symptomatic.
• Divarication of the recti — a midline bulge on sitting up, without a defect — not a hernia (see below).

Incisional and Parastomal Hernias

• Incisional hernia — through a previous surgical scar; occurs after a significant proportion of midline laparotomies, often in the first 1–2 years.
  • Risk factors — wound infection, obesity, smoking, steroids, diabetes, malnutrition, chronic cough, emergency surgery, poor closure technique; also after port sites.
  • Prevention — "small bites" closure technique, prophylactic mesh in some high-risk patients, treating wound infections promptly.
  • Features — bulge near the scar on standing or coughing; often a wide neck (lower risk of strangulation), but smaller or multiple defects can trap bowel.
  • Management — conservative (binder) or mesh repair (open or laparoscopic); very large hernias with "loss of domain" need specialist abdominal wall reconstruction; optimise weight and stop smoking first.
• Parastomal hernia — a hernia beside a stoma; very common (especially colostomies); causes bulging, difficulty with the stoma appliance, pain and obstruction; managed with support garments, or surgical repair (often with mesh) if symptomatic; prophylactic mesh is used at stoma formation in some centres.

Rarer Hernias

Hiatus and Diaphragmatic Hernias

• Sliding hiatus hernia (most) — the gastro-oesophageal junction slides up into the chest; associated with reflux; managed with PPIs and lifestyle measures; surgery (fundoplication) for selected patients (see the Upper GI page).
• Rolling (paraoesophageal) hiatus hernia — part of the stomach rolls up beside the oesophagus while the junction stays in place; can twist (gastric volvulus) or strangulate — chest pain, vomiting, inability to vomit or pass an NG tube; symptomatic ones are usually repaired.
• Congenital diaphragmatic hernia — in newborns (usually left-sided — Bochdalek); bowel in the chest, lung hypoplasia, breathing difficulty at birth (see the Neonatology chapter); Morgagni hernias — anterior, often found incidentally in adults.
• Traumatic diaphragmatic rupture — after blunt or penetrating trauma (usually left side); may present years later with bowel obstruction or breathlessness.

Incarceration, Obstruction and Strangulation

• Features of a complicated hernia:
  • Incarcerated — a lump that won't go back, often with discomfort but no systemic upset.
  • Obstructed — plus colicky abdominal pain, vomiting, distension and constipation.
  • Strangulated — a tense, tender, red or dusky lump, constant pain, fever, tachycardia, raised white count and lactate, peritonism; the skin may be discoloured.
• Management:
  • Resuscitation, analgesia, nil by mouth, IV fluids, NG tube if obstructed, bloods (lactate), urgent surgical review.
  • Gentle reduction ("taxis") may be attempted for a recently incarcerated, non-tender hernia with no signs of strangulation, with analgesia — then plan early repair.
  • Don't forcibly reduce a tender, possibly strangulated hernia — you may push dead bowel back into the abdomen, or reduce the sac with the bowel still trapped ("reduction en masse").
  • Emergency surgery for obstruction or strangulation — inspect the bowel, resect if non-viable, repair the defect (mesh may be avoided in contaminated fields).
• Which hernias are most likely to strangulate — those with a narrow neck: femoral, paraumbilical, indirect inguinal, obturator, Spigelian; direct inguinal and large incisional hernias with wide necks are lower risk.

Hernia Repair

• Inguinal hernia repair:
  • Open mesh repair (Lichtenstein) — under general, regional or local anaesthetic; day case; good for unilateral primary hernias and frail patients.
  • Laparoscopic repair (TEP — totally extraperitoneal, or TAPP — transabdominal preperitoneal) — mesh placed behind the muscles; preferred for bilateral and recurrent (after open) hernias and in women; needs general anaesthesia; quicker return to activity and less chronic pain in some.
  • Children — herniotomy (tying off the sac) without mesh.
• Femoral hernia repair — open (low or high approach) or laparoscopic, usually with mesh; emergency repair with possible bowel resection if strangulated.
• Umbilical, paraumbilical and epigastric — sutured repair for small defects; mesh for larger ones (lower recurrence).
• Incisional — mesh repair (open or laparoscopic); complex reconstruction (component separation) for large defects.
• Before surgery — optimise smoking, weight, diabetes and cough; check anticoagulants; consent including risks of recurrence and chronic pain.
• Mesh — reduces recurrence; complications include infection, chronic pain, and rarely adhesions or erosion; mesh for hernia repair remains standard (unlike vaginal mesh, which has restrictions in the UK).

Complications of Repair and Recovery

• Early — pain, bruising and haematoma (scrotal swelling), seroma, wound infection, urinary retention (especially after laparoscopic or spinal anaesthesia in older men).
• Later:
  • Chronic groin pain — in a minority (around 1 in 10 have some, a few have severe pain); nerve irritation (ilioinguinal, iliohypogastric, genitofemoral) — analgesia, nerve blocks, sometimes surgery.
  • Recurrence — a few per cent after mesh repair; higher after emergency repair, infection, obesity and smoking.
  • Testicular problems — ischaemic orchitis and atrophy (damage to testicular blood vessels), injury to the vas deferens (fertility).
  • Mesh infection (may need removal), bowel or bladder injury (rare, mainly laparoscopic).
• Recovery advice — walk from the day of surgery; light activities within days; usually avoid heavy lifting for about 4–6 weeks (follow the surgeon's advice); return to desk work in 1–2 weeks, manual work longer; driving when able to do an emergency stop without pain; check with insurers.

Divarication, Haematoma and Abdominal Wall Lumps

• Divarication of the recti (diastasis recti) — widening of the linea alba between the rectus muscles, causing a midline ridge on sitting up; common after pregnancy and in obesity; no risk of strangulation; physiotherapy (core exercises); surgery rarely needed.
• Rectus sheath haematoma — bleeding into the rectus sheath (anticoagulants, coughing, trauma, injections): sudden abdominal wall pain and a tender mass that doesn't cross the midline and becomes more obvious on tensing the abdominal muscles (Fothergill's sign); CT confirms; usually conservative (review anticoagulation, transfuse if needed); embolisation if bleeding continues.
• Other abdominal wall lumps:
  • Lipoma — soft, mobile, painless.
  • Epidermoid (sebaceous) cyst — skin-attached with a central punctum.
  • Scar endometriosis — a painful lump in a caesarean scar that swells with periods.
  • Desmoid tumour — firm, slowly growing mass in the muscle (after pregnancy, in familial adenomatous polyposis).
  • Sister Mary Joseph nodule — a hard lump at the umbilicus from metastatic abdominal or pelvic cancer (stomach, ovary, colon, pancreas).
  • Abscesses, skin cancers, injection site lumps (insulin lipohypertrophy).

Hernias in Children

• Inguinal hernias — more common in boys and in premature babies; always indirect (patent processus vaginalis); a groin or scrotal swelling that comes and goes with crying; high risk of incarceration in infants — refer promptly for herniotomy (urgently if under about 6 months or incarcerated; incarcerated hernias in infants can damage the testis or bowel).
• Hydroceles in infants — a fluid-filled sac (communicating with the abdomen in many) — transilluminates; most resolve by 1–2 years; surgery if persisting.
• Umbilical hernias — very common; most resolve by 4–5 years.
• Irreducible groin swelling in a child — consider incarcerated hernia, testicular torsion, torsion of an undescended testis, or an encysted hydrocele of the cord — urgent surgical assessment.
• See the Paediatric Gastroenterology and Surgery chapter.

Groin and Abdominal Wall Lumps at a Glance

Spot the Diagnosis

Exam-style Scenarios

1. An 82-year-old thin woman has vomited for 2 days with colicky abdominal pain and distension. She has had no previous surgery. There is a small, firm, tender lump in her right groin below and lateral to the pubic tubercle.
Answer: Obstructed (possibly strangulated) right femoral hernia.

• Resuscitate — IV fluids, analgesia, NG tube, bloods including lactate; consent and urgent theatre.
• Don't attempt forcible reduction; emergency repair with inspection of the bowel and resection if non-viable.
• Consider CT if the diagnosis is uncertain, but don't delay surgery for imaging if strangulation is likely.

2. A 58-year-old man has a right groin bulge for a year that goes away when he lies down. It causes mild aching after a long day at work. He smokes and has a chronic cough.
Answer: Symptomatic reducible right inguinal hernia.

• Offer elective repair (open mesh or laparoscopic); explain risks — chronic pain, recurrence, haematoma, retention, testicular problems.
• Optimise before surgery — stop smoking, investigate and treat the cough (chest X-ray if indicated), check for prostate symptoms and constipation.
• Advise on warning signs of incarceration or strangulation while waiting.

3. A 70-year-old man had a laparotomy for a perforated diverticulum 18 months ago, complicated by a wound infection. He now has a large bulge in his midline scar that is reducible. BMI 38, smoker, HbA1c 78.
Answer: Incisional hernia — optimise before elective repair.

• Weight loss, smoking cessation and better diabetes control reduce complications and recurrence.
• CT to assess the defect size and any other defects; consider an abdominal binder meanwhile.
• Mesh repair (open or laparoscopic, or complex reconstruction if very large) once optimised; urgent surgery if it becomes painful and irreducible.

4. A 7-week-old baby boy born at 32 weeks has a swelling in his left groin that appears when he cries and goes away when he settles.
Answer: Indirect inguinal hernia in a premature infant.

• Refer promptly to paediatric surgery for herniotomy — high risk of incarceration in infants.
• Teach parents the warning signs — a hard, tender swelling that doesn't go back, vomiting, distress — seek urgent help.
• Check the other side and the testes (undescended testis is more common in prematurity).

Key Points

• A hernia can be reducible, incarcerated, obstructed or strangulated; strangulation is an emergency.
• Richter's hernia can strangulate without obstruction.
• Inguinal hernias lie above and medial to the pubic tubercle; femoral hernias below and lateral.
• Indirect inguinal hernias pass lateral to the inferior epigastric vessels; direct ones medial (Hesselbach's triangle).
• Children's inguinal hernias are indirect — repair promptly, urgently in infants.
• Minimally symptomatic inguinal hernias in men can be watched; symptomatic ones repaired.
• All femoral hernias should be repaired — high strangulation risk; common in older women.
• Always examine hernial orifices in bowel obstruction.
• Obturator hernia — thin older woman, SBO, inner thigh pain (Howship–Romberg).
• Don't forcibly reduce a tender hernia; gentle taxis only for non-tender recent incarceration.
• Laparoscopic repair suits bilateral and recurrent inguinal hernias and women.
• Chronic groin pain and recurrence are the main long-term risks of repair.
• Optimise smoking, weight, cough and diabetes before elective repair.
• Divarication of the recti is not a hernia and doesn't strangulate.
• Rectus sheath haematoma — tender mass on anticoagulants, persists on tensing the muscles.

Guidelines and Further Reading

• HerniaSurge Group: International guidelines for groin hernia management
• European Hernia Society: Guidelines on incisional, umbilical, epigastric and parastomal hernias
• Royal College of Surgeons of England: Commissioning guide — groin hernia
• NICE: Laparoscopic surgery for inguinal hernia repair
• BNF — for current doses