Why This Station Is Tested
Inguinal region examination is tested in surgical OSCEs and covers one of the highest-yield differentials in clinical medicine. The station requires you to distinguish between inguinal and femoral hernias, identify a cough impulse, assess reducibility, and recognise other groin swellings including lymphadenopathy, varicocele, and hydrocele.
Anatomy Recap
| Structure | Location | Relevance |
|---|---|---|
| Inguinal canal | Above and medial to deep inguinal ring, exits at superficial ring | Indirect inguinal hernia track |
| Femoral canal | Below inguinal ligament, medial to femoral vein | Femoral hernia site |
| Deep inguinal ring | Midpoint of inguinal ligament | Indirect hernia origin |
| Superficial inguinal ring | Above pubic tubercle | Inguinal hernia exit |
Inguinal vs Femoral hernia mnemonic — NAVEL (from lateral to medial at femoral triangle):
Nerve, Artery, Vein, Empty space, Lymphatics — femoral hernia passes through the empty space medial to the vein.
Systematic Approach
1. Inspection
- Expose groin and genitalia appropriately (maintain dignity)
- Inspect standing if possible (hernias more visible erect)
- Look for: visible swelling, skin changes, asymmetry, surgical scars
- Ask patient to cough — visible cough impulse?
2. Palpation
Identify bony landmarks first: pubic tubercle (inguinal hernia is above and medial; femoral hernia is below and lateral to the pubic tubercle).
Assess the swelling:
- Size, shape, consistency, surface, temperature
- Is it tender?
- Can you get above it? (cannot get above an inguinoscrotal hernia — helps distinguish from hydrocele)
- Cough impulse: place hand over swelling and ask patient to cough — a transmitted impulse confirms a hernia
- Reducibility: gently attempt to reduce — do NOT force if irreducible
3. Percussion and Auscultation
- Hernia: may be resonant (bowel content) or dull (omentum)
- Bowel sounds may be audible over a bowel-containing hernia
Inguinal vs Femoral Hernia
| Feature | Inguinal (indirect) | Femoral |
|---|---|---|
| Position | Above and medial to pubic tubercle | Below and lateral to pubic tubercle |
| Sex | M >> F | F > M (but still common in M) |
| Relationship to ASIS-pubic tubercle (inguinal ligament) | Above ligament | Below ligament |
| Strangulation risk | Lower | HIGH — narrow neck |
| Reducibility | Often reducible | Often irreducible |
⚠️ Red Flag
Femoral hernias have a narrow neck and a high risk of strangulation — irreducible femoral hernias are surgical emergencies. Always assess for signs of bowel obstruction (pain, distension, vomiting, constipation) and strangulation (fever, peritonism).
Other Groin Swellings
| Swelling | Key Features |
|---|---|
| Lymphadenopathy | Multiple firm nodes; look for lower limb infection, STI, malignancy |
| Hydrocele | Transilluminates; cannot get above it in inguinoscrotal type; smooth, fluctuant |
| Varicocele | "Bag of worms" feel; more prominent standing/Valsalva; left side (drains to renal vein) |
| Saphena varix | Bluish, soft, disappears on lying down; cough impulse; transmitted thrill |
| Psoas abscess | Fluctuant, may be associated with TB or Crohn's |
| Undescended testis | No testis palpable in scrotum on same side |
Completing the Examination
"To complete my assessment I would examine the contralateral groin, examine the scrotum and testes, perform a digital rectal examination if indicated, and request an ultrasound to characterise the swelling further."
Frequently Asked Questions
"How do you distinguish an inguinal from a femoral hernia on examination?"
The key anatomical landmark is the pubic tubercle. Place your finger on the pubic tubercle: an inguinal hernia lies above and medial to the pubic tubercle (because it exits through the superficial inguinal ring), while a femoral hernia lies below and lateral to the pubic tubercle (because it passes through the femoral canal, which lies medial to the femoral vein and below the inguinal ligament). In practice, large or irreducible hernias can be difficult to classify anatomically, and ultrasound or CT may be required. Femoral hernias are more common in women but can occur in men — never exclude a femoral hernia based on sex alone.
"What is a cough impulse and how do you elicit it correctly?"
A cough impulse is the palpable or visible expansion of a hernia sac during a cough, caused by the sudden rise in intra-abdominal pressure forcing contents into the sac. To elicit it: place your flat hand or fingertips gently over the swelling, ask the patient to cough firmly, and feel for a transmitted impulse. A positive cough impulse strongly suggests a hernia. Note that a transmitted pulsation is not the same as a cough impulse — pulsatile swellings (femoral artery aneurysm, saphena varix) transmit pulsation continuously, not just on coughing. Always compare both sides.
"Why is a femoral hernia more dangerous than an inguinal hernia?"
Femoral hernias pass through the femoral canal, which has a rigid, unyielding neck formed by the inguinal ligament anteriorly, the lacunar ligament medially, and the femoral vein laterally. This narrow neck means the hernia contents (bowel or omentum) are at high risk of incarceration (cannot be reduced) and strangulation (blood supply compromised). Strangulated bowel leads to necrosis, perforation, and peritonitis within hours. Unlike inguinal hernias which may be managed electively if reducible, femoral hernias generally require prompt surgical repair due to the high strangulation risk.
"How do you examine for a varicocele and what is its significance?"
Examine the patient standing and ask them to perform a Valsalva manoeuvre or stand for a minute. Palpate the spermatic cord above the testis — a varicocele feels like a "bag of worms" (dilated tortuous veins of the pampiniform plexus) that becomes more prominent on standing and diminishes or disappears on lying down. Varicoceles occur predominantly on the left side (90%) because the left testicular vein drains at a right angle into the left renal vein, creating higher venous pressure. A new right-sided varicocele or one that does not decompress on lying raises suspicion of retroperitoneal malignancy compressing the vena cava and warrants urgent imaging.
"What findings suggest strangulation in a hernia examination?"
Signs of strangulation include: severe, constant pain (rather than intermittent dragging discomfort), irreducibility, a tense tender swelling with overlying skin erythema and oedema, fever, tachycardia, and signs of bowel obstruction (vomiting, absolute constipation, abdominal distension, high-pitched bowel sounds). The hernia will not have a cough impulse if strangulated. This is a surgical emergency — do not attempt forceful reduction. The patient requires resuscitation (IV access, fluids, analgesia, NG tube, catheter) and urgent surgical review. State this clearly to the examiner if you identify these features.
"What does transillumination confirm in a groin swelling?"
Transillumination is performed by placing a pen torch against the swelling in a darkened room — a fluid-filled structure transmits light (glows red), while a solid or gas-filled structure does not. Positive transillumination confirms the swelling contains clear fluid, consistent with a hydrocele or lymphatic cyst. Hernias containing bowel (gas) may transilluminate weakly but incompletely. A hydrocele transilluminates brilliantly. Important caveat: in neonates, bowel can transilluminate — context is key. In an OSCE, always offer transillumination when examining any scrotal or groin swelling.
Related guides: Hernia Examination OSCE · Testicular and Scrotal Examination OSCE · Abdominal Examination OSCE · Lymph Node Examination OSCE