An inguinal hernia is an abnormal protrusion of intraabdominal contents (most commonly fat) through the inguinal canal. Inguinal hernias are the most common type of groin hernia, and can be further subdivided based on anatomic location: an indirect inguinal hernia protrudes lateral to the inferior epigastric vessels through the deep inguinal ring, whereas a direct inguinal hernia protrudes medial to the inferior epigastric vessels through a defect in the posterior wall of the inguinal canal. An uncomplicated inguinal hernia typically manifests as a mass in the groin with or without pain (inguinodynia). Incarceration, obstruction, and strangulation of hernial contents are collectively referred to as complicated inguinal hernia. Inguinal hernia is a clinical diagnosis. Imaging, preferably with ultrasound, is indicated if the clinical diagnosis is uncertain. Surgery is the only definitive management of inguinal hernia and can be performed as an open surgery or laparoscopically. A strangulated inguinal hernia is a surgical emergency. In patients with an incarcerated hernia with or without bowel obstruction, manual reduction of the hernia may be considered as a temporizing measure before surgery. Conservative management may be considered in select patients with a small, uncomplicated inguinal hernia.
- Direct inguinal hernia: protrusion of abdominal and/or pelvic contents directly through the posterior wall of the inguinal canal
- Indirect inguinal hernia: protrusion of abdominal and/or pelvic contents into the inguinal canal through the deep inguinal ring
- Uncomplicated inguinal hernia: an inguinal hernia that is completely reducible and not associated with signs of bowel obstruction or strangulation
- Complicated inguinal hernia: an inguinal hernia that is either irreducible (incarcerated) or associated with mechanical bowel obstruction and/or strangulation
- Occult inguinal hernia: an inguinal hernia that is not identifiable on physical examination
|Overview of hernias|
|Inguinal hernia||Femoral hernia|
See “Femoral hernia” for further information.
- Sex: ♂ > ♀
Epidemiological data refers to the US, unless otherwise specified.
- Extends between the deep (internal) and superficial (external) ring
- Roof (superior): internal oblique and transversus abdominis muscles
- Floor (inferior): inguinal ligament (shelving edge of external oblique) and lacunar ligament (medially)
- Posterior wall: transversalis fascia laterally; conjoint tendon medially
- Anterior wall: external oblique aponeurosis and internal oblique muscle laterally
Hesselbach triangle borders
- Medially: rectus abdominis muscle
- Laterally: inferior epigastric vessels
- Inferiorly: inguinal ligament
Direct inguinal hernia
- Acquired condition
- Caused by weakening of the transversalis fascia
- Medial to the inferior epigastric blood vessels (within Hesselbach triangle) and lateral to the rectus abdominis
- Hernial sac protrudes directly through the posterior wall of the inguinal canal (without involvement of the spermatic cord or round ligament of the uterus)
- Only herniates through the superficial (external) ring
- Only surrounded by the external spermatic fascia
Indirect inguinal hernia
- Most commonly results from incomplete obliteration of processus vaginalis; during fetal development (but can also be acquired).
- May not become apparent until adulthood despite being present since birth.
- Lateral to the inferior epigastric blood vessels (outside Hesselbach triangle)
- Runs from the deep inguinal ring through the inguinal canal to the superficial (external) inguinal ring (in men, along with the spermatic cord)
- Surrounded by the external spermatic fascia, cremasteric muscle fibers, and internal spermatic fascia
- Indirect inguinal hernia may be associated with a communicating hydrocele.
Uncomplicated inguinal hernia 
- Typically manifests as an ill-defined mass in the inguinal region with the following features:
- Inguinodynia with no palpable groin mass is typically the only manifestation of an occult inguinal hernia. 
- Ask the patient to perform the Valsalva maneuver and observe for an in the inguinal region.
- Palpate the inguinal canal.
- The hernia is completely reducible and soft.
Female patients rarely present with visible bulges but often report a sensation of heaviness or dull discomfort in the groin or pelvis that is worsened by lifting, straining, or prolonged standing. 
Complicated inguinal hernia 
- Incarcerated hernia
- Obstructed hernia: : symptoms of mechanical bowel obstruction (sudden onset of pain, nausea, vomiting, abdominal distention, constipation or obstipation)
- Strangulated hernia
should not be attempted if there are any signs of strangulation!
- Medical history should include:
- Physical examination should include:
To avoid missing inguinal hernias, routinely in patients with unexplained and/or , especially in those with verbal impairment.
- Uncertain clinical diagnosis
- Suspected recurrent or occult inguinal hernia
- Consider preoperative imaging for complicated inguinal hernia.
- First line; : ultrasound of the groin 
- Inconclusive ultrasound findings: CT or MRI abdomen and pelvis
- Complicated inguinal hernia: Consider CT abdomen and pelvis with IV contrast. 
- Suspected occult inguinal hernia or recurrent inguinal hernia; consider any of the following modalities: 
- Visualization of the hernial sac with its contents (e.g., bowel, omentum)
- Uncomplicated inguinal hernia
- Free fluid and thickening of bowel wall within the hernial sac
- Dilated bowel loops within the abdomen (see “ ” for details)
Strangulated inguinal hernia 
- Absence of blood flow to the hernial contents
- Absence of peristalsis in bowel loops within the hernial sac
Do not delay emergency surgery for imaging in unstable patients with signs of or . 
Laboratory studies 
The following tests should be obtained in patients with strangulated inguinal hernia or incarcerated inguinal hernia with bowel obstruction for supportive diagnostic evidence and to assess for complications. 
Groin or scrotal mass 
|Overview of inguinal masses|
|Inguinal hernia||Direct|| || || |
|Femoral lymphadenopathy|| |
|Femoral arteriovenous fistula|| || |
|Psoas abscess|| || |
|Femoral artery aneurysm|| || |
- Round ligament varicosities
- Large cutaneous or subcutaneous masses in the inguinal region
A groin bulge with an expansile cough impulse above the inguinal ligament is diagnostic of an inguinal hernia. A femoral hernia typically manifests as a groin bulge below the inguinal ligament and lateral to the pubic tubercle. 
Groin pain 
If these diagnoses are chronic or recurrent, they may cause.
- Acute appendicitis
- Diverticulosis or acute diverticulitis
- Pathology of the hip joint
- Inflammatory bowel disease
- Lumbar disk herniation
- Testicular disorders
- Urinary tract infection
- Osteitis pubis
- Musculoskeletal pain
- Sports hernia: chronic groin pain due to an injury or weakness of the posterior wall of the inguinal canal; an actual hernia may or may not be present 
The differential diagnoses listed here are not exhaustive.
Critically ill patients with complicated inguinal hernias need to be stabilized and evaluated concurrently. Well-appearing patients with easily reducible hernias typically do not need further workup in the emergency department.
Complicated inguinal hernias
- Strangulated hernia and/or signs of mechanical bowel obstruction: emergency surgery (within hours)
- Incarcerated hernia without strangulation: Consider .
- Uncomplicated inguinal hernia: Recommend elective surgery; consider watchful waiting in selected patients.
Initial management and disposition 
- All patients
- Reducible hernia: Refer for outpatient surgical management (watchful waiting or elective hernia repair).
- Provide resuscitation as needed; see “ .”
- Assess for signs of obstruction and strangulation.
- Establish NPO status and provide supportive care as needed (e.g., , , , and ).
- No signs of : Consider as a temporizing measure. 
- Consider broad-spectrum IV antibiotics (see “Empiric antibiotic therapy for intraabdominal infection”). 
- Consider NG tube insertion for .
- Consult surgery urgently for operative management; do not attempt manual reduction.
Intestinal infarction can occur within 6 hours of strangulation. 
Risk factors associated with poor outcomes in incarcerated and strangulated hernias include older age, obesity (BMI > 30 kg/m2), prolonged duration of symptoms, female sex, and a delayed diagnosis. 
Manual reduction of an inguinal hernia 
- Description: A bedside procedure where hernia contents are manually guided back into the abdominal cavity through the fascial inguinal defect.
- Indication: Consider as a temporizing measure before surgery in patients with an incarcerated hernia with or without bowel obstruction.
- Contraindication: strangulated inguinal hernia
- Preparation: NPO, parenteral analgesia, consider procedural sedation
Successful hernia reduction: Observe the patient for 12–24 hours with . 
- Symptoms improve: Schedule an elective hernia repair as soon as possible.
- Symptoms worsen: immediate surgical consult to evaluate for recurrence or 
- Unsuccessful hernia reduction: urgent surgery (see “Surgeries for inguinal hernia”)
Manual reduction of hernial contents is contraindicated in patients with signs of a strangulated hernia, as necrotic bowel or omentum may be pushed into the abdominal cavity, which can lead to serious complications including peritonitis. 
Surgeries for inguinal hernia
Once the hernial contents are reduced (i.e., returned to the abdominal cavity), the goal of hernia surgery is to reinforce the posterior wall of the inguinal canal with a synthetic mesh or through primary tissue approximation. Emergency surgery is associated with an increased risk of complications; elective surgery is preferred when it is an option.
- Elective surgery
- Emergency surgery: complicated inguinal hernia
Hernioplasty (mesh repair)
- Definition: repair of a hernial defect using a synthetic mesh
- Indication: gold standard for inguinal hernia repair 
- Preferred in patients with complicated inguinal hernia or contraindications for laparoscopic repair 
- Procedures include Lichtenstein repair, in which a synthetic mesh is placed between the transversalis fascia and the external oblique aponeurosis to reinforce the posterior wall of the inguinal canal. 
- Laparoscopic surgery: preferred in patients with bilateral or recurrent inguinal hernia 
Herniorrhaphy (non-mesh repair)
- Definition: open surgical repair of a hernial defect using autologous tissue
- Indication: Consider in patients at high risk of surgical site infection. 
- Options: Shouldice repair
- Important consideration: Herniorrhaphy is associated with a greater risk of recurrence than hernioplasty. 
Conservative management 
Most patients who are managed conservatively will eventually require surgical repair.
- Indications 
- Symptoms significant enough to limit daily activities 
- Complicated inguinal hernia
- Female patients
- General recommendations 
All patients with inguinal hernia
- hernia reducibility and signs of obstruction and strangulation. , assessing for
- If signs of strangulated inguinal hernia.” are present, see “Acute management of
- Order abdominopelvic imaging (e.g., pelvic ultrasound) if the diagnosis is unclear.
- Refer easily reducible uncomplicated inguinal hernias for outpatient elective surgical management.
- Attempt 2 attempts). if for without signs of (maximum
- Observe patients with successful manual reduction with serial abdominal examinations (e.g., for 12–24 hours).
- Consult surgery urgently if manual reduction is unsuccessful.
Acute management of strangulated inguinal hernia
- Perform ABCDE assessment.
- Consult surgery immediately and do not attempt manual reduction.
- Establish NPO status.
- Establish IV access and obtain CBC, BMP, lactate, and other studies required for .
- Administer IV fluids, analgesics, and antiemetics.
- Start .
- Consider CT abdomen and pelvis with IV contrast once stable.
- Consider NG tube placement for .
- Consider Foley catheter placement
Preoperative complications 
- Incarcerated hernia: progression to mechanical bowel obstruction or strangulation of hernia sac contents
- Strangulated hernia
We list the most important complications. The selection is not exhaustive.
Special patient groups
Inguinal hernia in children
- Etiology and risk factors
Therapy: : surgery
- Premature infants with uncomplicated inguinal hernia: Surgery should be performed after discharge from the neonatal intensive care unit (NICU).
- If hernia can be reduced manually: Wait 24–48 hours before performing surgery to allow enough time for edema to decrease. 
- If hernia cannot be reduced manually: immediate surgery
- Asymptomatic inguinal hernia: within 14 days of diagnosis