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KEY FACTS

Terminology
- Protrusion of abdominal contents through femoral ring into femoral canal
Imaging
- Omental fat or bowel herniating into femoral canal medial to femoral veinand inferior to inferior epigastric vessels
- Femoral vein often indented or compressed by hernia sac
- Hernia sac located posterior and lateral to pubic tubercle
- Narrow, funnel-shaped neck
- 2x as common on right side compared to left
Top Differential Diagnoses
- Inguinal hernia - Inguinal hernias seen anteriorto horizontal plane of pubic tubercle - Abdominal contents within inguinal canal anteromedialto femoral vessels with extension into scrotum
- Obturator hernia - Hernia into superolateral aspect of obturator canal
- Lymphadenopathy
Clinical Issues
- Primarily occur in older women with 36% occurring in patients > 80 years old
- Relatively uncommon, representing only 2-4% of groin hernias in adults - ~ 1/10 as common as inguinal hernias - ~ 1/3 of groin hernias occur in women
- Highest risk of incarceration/strangulation (25-40%) among all groin hernias - 8-12x more prone to incarceration/strangulation than inguinal hernias
- Significant risk of mortality, primarily related to incarceration and intestinal obstruction - Mortality: 1% in 70-79 age group; 5% in 80-90 age group
- Symptomatic hernia (or newly discovered asymptomatic hernia) should undergo immediate surgical repair

TERMINOLOGY

Abbreviations
- Femoral hernia (FH)
Synonyms
- Crural hernia, enteromerocele, femorocele
Definitions
- Groin hernia with protrusion of abdominal contents through femoral ring into femoral canal

IMAGING

General Features

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
        - FH located posterior to plane of pubic tubercle
- 2x 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 veinand inferior to inferior epigastric vessels - Femoral vein often indented or compressed by hernia sac
- Hernia sac located posteriorand lateralto pubic tubercle
- Narrow funnel-shaped or pear-shaped neck, often best appreciated on coronal or sagittal images
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 narrow neck
Imaging Recommendations
- Best imaging tool
```
- CECT
```

DIFFERENTIAL DIAGNOSIS

Inguinal Hernia
- Abdominal contents within inguinal canal anteromedialto femoral vessels with extension into scrotum
- Seen anteriorto horizontal plane of pubic tubercle
- Does not involve femoral canal or compress femoral vessels
Obturator Hernia
- Hernia into superolateral obturator canal
- Typically occurs in older women (80-90%) with high risk of incarceration
Lymphadenopathy
- When medial to femoral vessels, can theoretically mimic FH on clinical exam but distinction easily made with CT

PATHOLOGY

General Features

Etiology

- May be partially attributable to congenital defect in insertion of transversalis fascia to ileopubic tract
- Right-sided predominance thought to be secondary to delay during development in closure of processus vaginalis, as right testicle normally descends slower during development
        - Sigmoid colon may exert pressure on left femoral canal during development and make left-sided FHs less likely
- Femoral ring connective tissues may dilate during pregnancy, placing women at increased risk for FH
- Associated with increased intraabdominal pressure

CLINICAL ISSUES

Presentation

Most common signs/symptoms

- Swelling, groin discomfort, vague pelvic discomfort
- Lump usually felt at top of thigh, below groin crease
- Pain is uncommon in absence of strangulation
- 1/3 of patients asymptomatic at time of diagnosis

Other signs/symptoms

- Nausea, vomiting, severe pain with strangulated hernia
- Difficult to diagnose clinically, especially in obese patients, due to deep location of femoral canal

Demographics

Age

- 36% occur in patients > 80 years old
- 16% occur in 7th decade
- < 1% of all groin hernias in children

Sex
```
- Predominantly women (M:F = 1:10)
```

Epidemiology

- ~ 2-4% of groin hernias in adults
- ~ 1/10 as common as inguinal hernias
- ~ 1/3 of groin hernias in women
- 10% of women and 50% of men with FHs also have coexisting inguinal hernias at diagnosis

Natural History & Prognosis
- Complications - High risk of incarceration &/or strangulation (25-40%), primarily due to narrow neck and unyielding margins of femoral ring - Highest rate of incarceration of all groin hernias - 8-12x more prone to incarceration/strangulation than inguinal hernias - Rarely, inflamed appendix extends into hernia sac (De Garengeot hernia)
- Morbidity and mortality - Primarily related to incarceration/bowel obstruction - Mortality: 1% in 70-79 age group; 5% in 80-90 age group
Treatment
- Symptomatic hernia (or newly discovered asymptomatic hernia) should undergo immediate surgical repair
- Longstanding, asymptomatic hernias may theoretically be treated conservatively with watchful waiting
- Can be repaired either with laparoscopic or open surgery (without any consensus in literature)

DIAGNOSTIC CHECKLIST

Image Interpretation Pearls
- FHs lie medial to femoral vein and inferior to inferior epigastric vessels, often compressing femoral vein

75526537-4844-4ee0-b8ce-a4b2d77fd2bf

References

Selected References

Differential diagnosis

Abdominal Wall Mass

DDX:d51e2268-67b6-4a60-9222-f5a86f61ddec

Defect in Abdominal Wall (Hernia)

DDX:5af046fa-59ef-45b5-952b-acbcdee36196

Groin Mass

DDX:160e727f-dabe-4187-aa46-c29625076cc5

Small Bowel Obstruction

DDX:ad8209f0-71e5-4496-860f-d2724ca22892

Cluster of Dilated Small Bowel

DDX:6a20ee48-b80a-4d67-9011-7a3c7176ef79

Cases

{'cases': [{'authors': [{'key': 'b61b8522-59ff-48f3-aaeb-65cc6d64aab2', 'value': 'Tracy A Jaffe, MD'}], 'caseVersionId': '2549544c-ebb1-4b6c-aaa2-c619e125e620', 'description': 'This is a classic illustration of a patient with small bowel obstruction from an incarcerated femoral hernia. \n\nThe axial images of the upper abdomen demonstrate dilated small bowel (arrow, #1, 2). Distal small bowel is decompressed (curved arrow, #3). Despite the streak artifact caused by the patients total hip arthroplasty, one can easily identify a knuckle of small bowel within the femoral canal, the source of the patients small bowel obstruction (open arrow, #4, 5). \n\nComment: Femoral hernias are more prone to incarceration than inguinal hernias, and mortality is closely associated with intestinal obstruction. This patient went on to exploratory laparotomy, excision of necrotic small bowel, and repair of the femoral hernia.', 'history': 'Elderly women with vomiting and abdominal pain.', 'imagePoolId': '2c01b04f-cdee-47c1-8e03-1f25f22a1694', 'name': 'Strangulated small bowel', 'teachingPoint': None, 'demographics': '74 Years old female'}, {'authors': [{'key': 'b61b8522-59ff-48f3-aaeb-65cc6d64aab2', 'value': 'Tracy A Jaffe, MD'}], 'caseVersionId': '26c94b87-a3cc-4ab3-96d8-e3631e5cdc1d', 'description': 'This case illustrates a femoral hernia which has become incarcerated in the femoral canal. \n\nThe images of the upper abdomen demonstrate dilated small bowel (arrows, #1, 2). More inferior images demonstrate decompressed distal small bowel suggesting a small bowel obstruction (open arrow, #3). Even more inferiorly we identify the source of obstruction, small bowel trapped in the femoral canal (curved arrow, #4). \n\nCoronal reformation (#5) confirms the location of the hernia (arrow). The neck of a femoral hernia is below the inguinal ligament and lateral to the pubic tubercle. The hernia is medial to the femoral vessels. Femoral hernias occur more frequently in women and may become incarcerated, as in this case (8-12 times more likely to become trapped than inguinal hernia).', 'history': 'Middle-aged patient with right groin pain and nausea.', 'imagePoolId': '09327dee-e765-494a-ab29-ed7c86d02bcf', 'name': 'Incarcerated', 'teachingPoint': None, 'demographics': '57 Years old female'}, {'authors': [{'key': '3d84d682-9451-4b02-99b2-e34970a5b440', 'value': 'Michael P. Federle, MD, FACR'}], 'caseVersionId': '2702a000-04be-4be1-89c1-4586d0a4e415', 'description': 'CECT shows massive distension of small bowel segments. Some distal small bowel (open arrow, #3) and the colon are collapsed, indicating a distal mechanical small bowel obstruction. The cause of the obstruction is seen as a femoral hernia (arrow, #4). Note that the herniated bowel lies just medial to the femoral vessels.', 'history': 'Young woman with abdominal pain and distention.', 'imagePoolId': '2cce5cc7-6d4d-4106-bacf-876353db273d', 'name': 'With small bowel obstruction', 'teachingPoint': None, 'demographics': '40 Years old female'}, {'authors': [{'key': 'b61b8522-59ff-48f3-aaeb-65cc6d64aab2', 'value': 'Tracy A Jaffe, MD'}], 'caseVersionId': 'a32e13a0-dfd7-4b77-9bbd-f7862d44ee94', 'description': 'This is a typical presentation of small bowel obstruction caused by a femoral hernia. \n\nAxial CECT images of the upper abdomen demonstrate multiple dilated, fluid-filled small bowel loops (arrow, #1). Image of the pelvis illustrates the source of obstruction, a knuckle of small bowel incarcerated in the femoral canal (arrow, #2). The hernia is protruding posterior to the inguinal ligament, medial to the femoral vessels (open arrow, #2). This is confirmed on the coronal reformation (arrow, #3). As expected, this femoral hernia has a narrow neck and "pear" shape.', 'history': 'Elderly patient with abdominal pain and obstructive symptoms.', 'imagePoolId': '174be9c1-80e6-4d13-9e6d-70a1749addec', 'name': 'Small bowel obstruction', 'teachingPoint': None, 'demographics': '80 Years old female'}, {'authors': [{'key': '49dc75da-ca12-45cb-97fc-2fe88198512c', 'value': 'Erik K Paulson, MD'}], 'caseVersionId': 'a7464dd1-c572-40a7-ad52-eca02e8f08f4', 'description': 'This case illustrates typical findings of a small bowel obstruction, due to a femoral hernia. \n\nImage #1 shows dilated small bowel (arrow) and decompressed distal small bowel (curved arrows).\n\nImages #2 and #3 show a loop of bowel (arrow) coursing into the femoral ring, medial to the femoral vessels, which represents the transition point from dilated to decompressed bowel and is the cause of the small bowel obstruction. Note the decompressed sigmoid colon (curved arrow, #2) with diverticula.\n\nCoronal reformation (#4) nicely demonstrates the incarcerated loop of small bowel (arrow) within the femoral ring.', 'history': 'Elderly woman with abdominal pain, nausea and vomiting. ', 'imagePoolId': '8bda08be-775a-4b9a-85cb-a9265e0afef8', 'name': 'Femoral hernia', 'teachingPoint': None, 'demographics': '80 Years old female'}, {'authors': [{'key': 'b61b8522-59ff-48f3-aaeb-65cc6d64aab2', 'value': 'Tracy A Jaffe, MD'}], 'caseVersionId': 'c566f2ee-e12d-4d71-947f-0fea65361014', 'description': 'This patient was referred for imaging of a palpable abnormality in the right groin. \n\nCECT images of the pelvis demonstrate nondilated, contrast-filled loops of small and large bowel (#1, 2). Axial image inferior to the pubic symphysis (#3) demonstrate a fluid-filled structure with a "pear" shape seen medial to the femoral vessels (arrow). This structure is also identified on the coronal image (arrow, #4). This is a femoral hernia without incarceration. The hernia is low within the femoral canal and the neck is below the inguinal ligament. \n\nComment: This femoral hernia was identified prior to bowel strangulation and the patient went on to surgical repair without small bowel resection.', 'history': 'Elderly female with pain in right groin.', 'imagePoolId': 'd5c2829f-f972-4a8c-a04b-c75a93e2b33d', 'name': 'Nondilated small bowel', 'teachingPoint': None, 'demographics': '78 Years old female'}, {'authors': [{'key': '3d84d682-9451-4b02-99b2-e34970a5b440', 'value': 'Michael P. Federle, MD, FACR'}], 'caseVersionId': 'cdf131d2-9f11-448e-b3be-3953c29a91c5', 'description': 'A supine radiograph (#1) shows distended small bowel and minimal colonic gas.\n\nCT shows fluid distended small bowel segments in the pelvis. The distended bowel could be followed into a femoral hernia (arrow, #3, 4). Note the close relationship of the hernia to the femoral vessels at the level of the symphysis pubis.', 'history': 'Elderly woman with abdominal pain.', 'imagePoolId': 'e8a7cd5a-90fd-49a9-83df-4e285cc98b10', 'name': 'With bowel obstruction', 'teachingPoint': None, 'demographics': '76 Years old female'}], 'caseType': 'typical', 'name': 'TYPICAL'}

Images

Selected Images

Graphic 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.

Axial CECT demonstrates the typical position of a femoral hernia . Note that the herniated loop of small bowel lies just medial to the femoral vessels .

Axial CECT shows a loop of thickened, hyperemic bowel herniating into the right groin medial to the femoral vessels.

Coronal CECT in the same patient demonstrates multiple dilated loops of small bowel with abrupt narrowing at the level of a segment of bowel coursing into the femoral ring, medial to the femoral vessels , compatible with small bowel obstruction secondary to a femoral hernia.

Additional Images

Axial CECT shows a femoral hernia with a small bowel obstruction. Note the loop of bowel entrapped in the right femoral canal .

Axial CECT at higher level in the same patient reveals a small bowel obstruction .

Axial CECT shows an incarcerated femoral hernia in the femoral canal. Note the decompressed distal small bowel, suggesting a small bowel obstruction .

Axial CECT in the same patient at a lower level identifies the source of the obstruction: Small bowel trapped in the femoral canal .

Coronal CECT reformation of a femoral hernia causing small bowel obstruction shows that the neck of the hernia is medial to the femoral artery . Note the proximal dilation of the small bowel due to obstruction .

Coronal reformation in the same patient clearly demonstrates a herniated loop of small bowel .

Axial CECT at a lower level demonstrates herniated bowel medial to the femoral vein .

Axial CECT shows a left femoral hernia containing a "knuckle" of strangulated bowel.

Axial CECT in an older woman shows a right femoral hernia and pessary .

Axial CECT shows a right femoral hernia containing small bowel that caused obstruction.

Axial CECT in an 80-year-old woman with abdominal pain, fever, and nausea shows a loop of bowel coursing into the femoral ring medial to the femoral vessels; the transition point from the dilated to the decompressed bowel, causing a small bowel obstruction. Note the presence of diverticula within the decompressed sigmoid colon.

Coronal CECT reformation in the same patient demonstrates an incarcerated loop of small bowel within the femoral ring.

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KEY FACTS

Terminology

Imaging

Top Differential Diagnoses

Clinical Issues

TERMINOLOGY

Abbreviations

Synonyms

Definitions

IMAGING

General Features

Location

Morphology

CT Findings

Ultrasonographic Findings

Radiographic Findings

Imaging Recommendations

Best imaging tool

DIFFERENTIAL DIAGNOSIS

Lymphadenopathy

PATHOLOGY

General Features

Etiology

CLINICAL ISSUES

Presentation

Most common signs/symptoms

Other signs/symptoms

Demographics

Age

Sex

Epidemiology

Natural History & Prognosis

Treatment

DIAGNOSTIC CHECKLIST

Image Interpretation Pearls

References

Selected References

Differential diagnosis

Abdominal Wall Mass

Defect in Abdominal Wall (Hernia)

Groin Mass

Small Bowel Obstruction

Cluster of Dilated Small Bowel

Cases

Images

Selected Images

Additional Images

29 KiB

Raw Permalink Blame History