Hernia Ultrasound: Inguinal, Femoral, Umbilical, and Sports Hernia

Hernia ultrasound is a straightforward exam once you understand the anatomy — but the anatomy of the inguinal canal trips up new sonographers. Here's a practical guide to the most common hernia types you'll encounter.

Why Ultrasound for Hernias?

• Dynamic assessment: can demonstrate hernia with Valsalva that isn't apparent at rest
• No radiation (unlike CT)
• Evaluates soft tissue contents of hernia sac
• Real-time imaging while the patient reproduces their symptoms
• Distinguishes inguinal from femoral from other groin masses

Inguinal Hernia Anatomy Review

The inguinal canal runs obliquely from the deep (internal) inguinal ring to the superficial (external) inguinal ring.

• Deep inguinal ring: Just above the midpoint of the inguinal ligament, lateral to the inferior epigastric vessels
• Superficial inguinal ring: Just above the pubic tubercle

Inferior epigastric vessels are your key landmark — they course medially along the posterior inguinal wall. They are the anatomical divider between direct and indirect hernias.

Direct hernia: Hernia sac protrudes through the posterior wall of the inguinal canal, medial to the inferior epigastric vessels (through Hesselbach's triangle).

Indirect hernia: Hernia sac enters through the deep inguinal ring, lateral to the inferior epigastric vessels, and courses through the inguinal canal.

In men, indirect hernias may extend into the scrotum. In women, they follow the round ligament.

Scanning Technique — Inguinal Region

Probe: 5–12 MHz linear transducer.

Patient position: Supine initially, then upright if the hernia is not demonstrated supine.

Start with color Doppler: Identify the femoral vessels (common femoral artery and vein) at the inguinal crease — these are your landmarks. The inferior epigastric vessels branch from the external iliac and can be traced medially from the femoral vessel area.

Step-by-Step Protocol

1. Identify the femoral vessels in transverse — CFA, CFV side by side at the inguinal crease
2. Trace medially following the inguinal canal — you're looking for the inguinal canal as it courses toward the pubic tubercle
3. Identify the inferior epigastric artery and vein — they appear as a pulsatile and non-pulsatile pair coursing toward the umbilicus
4. Assess the canal in longitudinal — sweep medially to laterally along the canal axis
5. Apply Valsalva: Ask the patient to bear down hard (like pushing a bowel movement). Watch for herniation of fat or bowel into the canal
6. If upright: Have the patient stand and repeat — many hernias only appear with gravity and Valsalva

What You're Looking For

Herniated fat (indirect fat hernia): Echogenic fat protruding through the ring. On Valsalva, you'll see it push through and enlarge. May reduce when Valsalva is released.

Bowel-containing hernia: You'll see a tubular structure (bowel loop) with or without peristalsis within the hernia sac. Gas in the bowel creates echogenic foci with shadowing.

Fluid-containing sac: Simple fluid-filled sac (hydrocele of the canal of Nuck in women; communicating hydrocele in men).

Strangulated hernia: Non-reducible hernia with absent blood flow on Doppler within the bowel loop or fat — urgent finding.

Femoral Hernia

Femoral hernias occur inferior and medial to the inguinal ligament, through the femoral canal (medial to the femoral vein). They are more common in women and have a higher risk of incarceration than inguinal hernias because the femoral ring is rigid.

Sonographic appearance:

• Mass in the groin, medial and inferior to the femoral vein
• May be small and easily missed
• Contains fat or bowel
• Key: it's BELOW the inguinal ligament (inguinal hernias are ABOVE it)

Clinical importance: Femoral hernias incarcerate more readily than inguinal hernias. A tender, non-reducible femoral hernia is urgent.

Umbilical and Epigastric Hernia

Umbilical hernia: Defect through the umbilical ring.

• Measure the fascial defect (width)
• Document contents (fat vs bowel)
• Note reducibility on Valsalva

Epigastric hernia: Defect in the linea alba between the umbilicus and xiphoid. Often contains only fat (omentum) and may be clinically painful despite small size.

Incisional hernia: Defect at a prior surgical scar. May be large, complex, and contain multiple bowel loops.

Sports Hernia (Athletic Pubalgia)

Sports hernia is not a true hernia — it's a complex of posterior inguinal wall weakness and musculotendinous injuries around the pubic symphysis. Common in soccer players and athletes with repetitive twisting.

Ultrasound findings:

• Thickening or tearing of the posterior inguinal wall
• Adductor tendon pathology at the pubic symphysis
• Bulging of the posterior wall with Valsalva (without true fascial defect)
• No bowel or fat herniation through a ring

This is a clinical diagnosis — ultrasound is supportive. Compare to the contralateral side.

Urgent Findings: Incarcerated and Strangulated Hernia

Incarcerated hernia: Contents cannot be reduced back into the abdomen. May still have blood flow.

Strangulated hernia: Blood supply to the hernia contents is compromised. Surgical emergency.

Signs of strangulation on ultrasound:

• Absent Doppler flow within bowel loop or fat inside hernia
• Thickened bowel wall
• Echogenic free fluid surrounding the hernia
• Dilated bowel proximal to the hernia

If you see these findings, flag the radiologist immediately.

Reporting Language

• "No hernia identified at rest or with Valsalva maneuver bilaterally. Normal inguinal canals."
• "Right indirect inguinal hernia containing echogenic fat, extending through the deep inguinal ring lateral to the inferior epigastric vessels. Contents are reducible with release of Valsalva. No bowel within the hernia sac. Fascial defect at the deep ring measures approximately 1.5 cm."
• "Left femoral hernia containing a fat-filled sac, medial to the left femoral vein, below the inguinal ligament. The contents are non-reducible. No Doppler flow identified within the sac contents — findings raise concern for strangulation. Urgent surgical evaluation is recommended."

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SonoBuddy's Protocols section includes inguinal hernia scanning steps and anatomy diagrams.