(Left) Illustration of a femoral hernia demonstrates a characteristic “knuckle” of small bowel closely associated with the femoral vein . Femoral hernias are usually found medial to the femoral vessels with frequent compression of the femoral vein.
(Right) Axial CECT demonstrates a herniated small bowel loop lying within the femoral canal, compressing the femoral vessels, compatible with a femoral hernia.
(Left) Axial CECT shows a loop of thickened, hyperemic bowel herniating into the right groin medial to the femoral vessels. Notice that the femoral vein is being compressed, and the herniated bowel lies posterolateral to the pubic tubercle.
(Right) Coronal CECT in the same patient shows multiple dilated small-bowel loops with a transition point within the hernia. This thickened, hyperenhancing bowel within the hernia sac was found to be ischemic at surgery. Femoral hernias are at high risk for strangulation and obstruction.
TERMINOLOGY
Abbreviations
• Femoral hernia (FH)
Synonyms
• Crural hernia, enteromerocele, femorocele
Definitions
• Protrusion of abdominal contents through femoral ring into femoral canal
IMAGING
General Features
• Best diagnostic clue
• Location
Protrusion of hernia sac contents at right angle to inguinal canal through femoral ring into femoral canal
– Posterior to inguinal ligament, anterior to pubic ramus periosteum (Cooper ligament), and medial to femoral vessels
Inguinal ligament not visible on CT as discrete structure, but horizontal plane connecting pubic tubercles defines plane of inguinal ligament
– Femoral hernia posterior to plane of pubic tubercle
Twice as common on right side compared to left
• Morphology
Narrow neck with characteristic pear shape
CT Findings
• Omental fat or bowel herniating into femoral canal medial to femoral vein and inferior to inferior epigastric vessels
Femoral vein indented/compressed by hernia sac
• Hernia sac located posterior and lateral to pubic tubercle
• Narrow, funnel-shaped, or pear-shaped neck
Ultrasonographic Findings
• Hernia sac visualized extending medial to femoral vein
• Hernia sac may be easier to define with Valsalva maneuver
Radiographic Findings
• Herniography: Hernia curves smoothly over superior pubic ramus on all projections
Pear-shaped hernia sac with a narrow neck
Imaging Recommendations
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Abdominal contents within inguinal canal anteromedial to femoral vessels with extension into scrotum
closely associated with the femoral vein 
. Femoral hernias are usually found medial to the femoral vessels with frequent compression of the femoral vein.
lying within the femoral canal, compressing the femoral vessels, compatible with a femoral hernia.
herniating into the right groin medial to the femoral vessels. Notice that the femoral vein 
is being compressed, and the herniated bowel lies posterolateral to the pubic tubercle.
within the hernia. This thickened, hyperenhancing bowel within the hernia sac was found to be ischemic at surgery. Femoral hernias are at high risk for strangulation and obstruction.
