Femoral hernia
A femoral hernia is a protrusion of abdominal contents through the femoral canal, just below the groin crease. It accounts for a small minority of groin hernias but is responsible for a disproportionate share of hernia emergencies. The reason is anatomical and unforgiving: the femoral canal is a small, rigid, unyielding space, so a hernia entering it is far more likely to become trapped and to have its blood supply cut off. The practical consequence is straightforward — a femoral hernia should be repaired when it is found, not watched.
How they form
Below the inguinal ligament, the femoral vessels pass from the abdomen into the thigh through the femoral sheath. The sheath has three compartments: the femoral artery laterally, the femoral vein in the middle, and medially a small potential space containing fat and a lymph node — the femoral canal. Its purpose is to allow the femoral vein to distend.
The canal's boundaries are what make the hernia dangerous:
- anteriorly — the inguinal ligament
- posteriorly — the pectineal (Cooper's) ligament, overlying bone
- medially — the sharp, unyielding edge of the lacunar ligament
- laterally — the femoral vein
Three of the four boundaries are rigid ligament or bone. When a loop of bowel enters this narrow ring and then swells, it cannot easily retreat, and the sharp lacunar ligament acts as a constricting band. Venous drainage is obstructed first; the contents become congested and swell further; arterial inflow then fails; and the trapped tissue becomes ischaemic. This can happen within hours.
Femoral hernias are considerably commoner in women, reflecting a wider pelvis and femoral canal, and are associated with increasing age, multiparity, weight loss, chronically raised abdominal pressure, and previous inguinal hernia repair — where the repair can push the weakness downward into the femoral canal.
Richter's hernia
This deserves separate mention because it is a genuine diagnostic trap and is particularly associated with femoral hernias. In a Richter's hernia, only part of the circumference of the bowel wall is caught in the defect. The bowel lumen therefore remains patent, so the patient continues to pass stool and flatus and has no obstruction — yet the trapped segment of wall becomes ischaemic and can perforate. A patient with a tender groin lump and no obstructive symptoms may still have dying bowel. This is the reason a tender irreducible femoral lump is taken seriously regardless of bowel function.
Symptoms
- a small lump in the upper thigh, below and lateral to the pubic tubercle, and below the inguinal ligament — in contrast to an inguinal hernia, which appears above and medial to it
- often small and easily overlooked, particularly in obese patients
- frequently not reducible, because of the narrow neck
- dragging discomfort in the groin
- a significant proportion present for the first time as an emergency, with no prior awareness of a hernia at all
Emergency features: a tender, firm, irreducible lump; colicky abdominal pain, vomiting, distension and absolute constipation indicating obstruction; overlying redness, fever and systemic illness indicating strangulation. Any of these requires immediate assessment.
How the diagnosis is made
Examination is the basis: the key is the relationship of the lump to the pubic tubercle. In practice the distinction is not always easy, particularly in obese patients or when the hernia is inflamed, and femoral hernias are not infrequently mistaken for enlarged lymph nodes, a saphena varix, a lipoma, a psoas abscess or a femoral artery aneurysm.
Ultrasound is a useful first investigation. CT is preferred in the emergency setting and in obese patients, and will demonstrate the hernia, its contents, and any obstruction or ischaemia. In an unwell patient with bowel obstruction and no obvious cause, the groins must be examined carefully — a missed femoral hernia is a well-recognised cause of unexplained obstruction, particularly in elderly women.
Treatment
All femoral hernias should be repaired, and promptly. Watchful waiting, which is reasonable for a minimally symptomatic inguinal hernia in a man, is not appropriate here. The risk of strangulation within the first months after diagnosis is substantial, and emergency repair carries far higher morbidity and mortality than elective repair — often in elderly patients, often requiring bowel resection.
Elective repair
The objective is to close the femoral canal. Approaches:
- Laparoscopic or robotic preperitoneal repair (TEP or TAPP) — increasingly the preferred elective approach. A single mesh placed in the preperitoneal space covers the femoral, direct and indirect defects together, which matters because coexisting defects are common. Recovery is fast.
- Open preperitoneal approach — entering above the inguinal ligament, allowing assessment of bowel viability and mesh placement over all groin defects.
- Open low (crural) approach — a small incision directly over the lump, with a mesh plug or suture repair closing the canal. Simple, performable under local anaesthetic, suited to frail patients, but gives limited access if bowel requires inspection.
Emergency repair
Where the hernia is strangulated, the contents must be assessed. The surgical difficulty is that reducing the hernia requires division of the constricting lacunar ligament, and an aberrant obturator artery — the so-called "corona mortis" — runs close to this ligament in a proportion of people and can bleed dramatically if divided blindly. Non-viable bowel is resected. Where there is contamination, primary tissue repair or biological mesh may be preferred to synthetic mesh.
Recovery
Elective repair is usually a day-case procedure, with return to normal activity in one to three weeks depending on approach. Emergency repair with bowel resection is a considerably larger undertaking, with a hospital stay of several days to weeks and a recovery measured in months, particularly in elderly patients.
The contrast between the two is the entire argument for early repair, and is worth putting to patients plainly.
When to seek help urgently
A groin or upper thigh lump that becomes painful, firm and cannot be pushed back requires immediate emergency assessment — even if you are still passing stool and wind normally, because only part of the bowel wall may be trapped. Vomiting, abdominal distension or feeling systemically unwell makes it more urgent still.
Common questions
How is this different from an ordinary groin hernia?
It comes through a different and much narrower opening, slightly lower down. That narrow, rigid opening means the contents are far more likely to become trapped and to lose their blood supply. It is less common than the ordinary groin hernia but considerably more likely to cause an emergency.
Why can't I just watch it?
Because the risk of the hernia becoming trapped is significantly higher than for an ordinary groin hernia, and the risk is greatest in the first months after it appears. An emergency operation for a trapped femoral hernia may involve removing a piece of bowel and carries far more risk than a planned repair, which is usually a straightforward day-case procedure.
Why are they commoner in women?
Because the pelvis is wider and the small channel through which the hernia passes is correspondingly larger. They are still not common overall, but among groin hernias in women a femoral hernia is a much more likely finding than it is in men.
I have a tender lump but my bowels are working normally. Is that reassuring?
Unfortunately not, in this particular hernia. Sometimes only part of the circumference of the bowel becomes trapped, so food continues to pass normally while the trapped portion loses its blood supply. Normal bowel function does not rule out a serious problem, which is why a tender lump that will not go back needs assessing straight away.
I was told I had a swollen gland in my groin. Could it have been this?
It is possible — femoral hernias are small and are sometimes mistaken for a lymph node, a varicose vein or a fatty lump, particularly if weight makes examination difficult. If a groin lump persists, an ultrasound or CT scan settles the question, and it is reasonable to ask for one.
What does the operation involve?
Closing the narrow opening, usually with a small piece of mesh. It can be done through a small cut over the lump, or by keyhole surgery from inside, which has the advantage of covering all the potential weak points in the groin at once. Both are usually day-case operations.
Can it come back?
Recurrence after a properly performed mesh repair is uncommon. A femoral hernia appearing after a previous ordinary groin hernia repair is a recognised situation, which is one reason a repair that covers the whole groin area is often preferred.
Related conditions
Other conditions of the hernias & abdominal wall covered on this site:
- Inguinal hernia (groin hernia)
- Umbilical and paraumbilical hernia
- Epigastric hernia
- Incisional hernia
- Parastomal hernia
- Diastasis recti (divarication of the recti)
- Incarcerated and strangulated hernia
- Rare hernias — Spigelian, lumbar, obturator and others
This page provides general information and does not replace an individual medical consultation. A painful, irreducible groin lump is a medical emergency requiring immediate assessment.