Rare external hernias

These include:

Spigelian hernias (1)

• occurs through the Spigelian fascia (the aponeurosis of the transversus abdominis muscle) along the semilunar line, typically at or below the level of the arcuate line.
• represents only 0.12% to 2% of all abdominal wall hernias. It is most frequently found in individuals over 60 years old and is slightly more common in females.
• because the defect is surrounded by rigid, tight fascial layers, approximately 24% to 25% of cases present as surgical emergencies due to acute incarceration or strangulation.

Lumbar hernias (2)

• these are rare posterior/lateral abdominal wall hernias that protrude through defects in the lumbar region. They are structurally confined by two specific anatomical regions - the Grynfelt-Lesshaft Triangle; the superior lumbar triangle (more common) - and the Petit Triangle; the inferior lumbar triangle.
• they typically occur spontaneously due to tissue weakness, secondary to blunt trauma, or as an iatrogenic complication following open retroperitoneal surgeries (such as open renal surgery).

Obturator hernias (3)

• the hernia sac protrudes through the obturator foramen alongside the obturator vessels and nerves.
• account for 0.05% to 1.5% of all groin hernias and are overwhelmingly seen in emaciated, elderly, multiparous females (often referred to classically as the ‘little old lady's hernia’) due to a lack of protective pelvic fat.
• often lack a visible external bulge and present instead as an unexplained small bowel obstruction. It may present with the Howship-Romberg sign (pain radiating down the medial thigh to the knee caused by compression of the obturator nerve).

Rare eponymous external & groin hernias are categorized by their specific anatomical contents or structural anomalies:

• Littre’s hernia: any external abdominal wall hernia (most commonly inguinal or femoral) that specifically contains a Meckel's diverticulum. (4)
• Amyand’s hernia: a rare subset of inguinal hernias containing the vermiform appendix, which may or may not be acutely inflamed. (5)
• De Garengeot hernia: a rare subset of femoral hernias containing the vermiform appendix. (6)
• Ischiatic (sciatic) hernia: a pelvic floor hernia protruding through the greater or lesser sciatic foramen, frequently presenting with pelvic or gluteal pain. (7)

Reference

1. Skandalakis PN, Zoras O, Skandalakis JE, Mirilas P. Spigelian hernia: surgical anatomy, embryology, and technique of repair. Am Surg. 2006 Jan;72(1):42-8
2. Sharmar P. Lumbar Hernia. Med J Armed Forces India. 2011 Jul 21;65(2):178–179.
3. Gilbert JD, Byard RW. Obturator hernia and the elderly. Forensic Sci Med Pathol. 2019 Sep;15(3):491-493.
4. Preda S et al. Management of Littre Hernia - Case Report and Systematic Review of Case Reports. J Clin Med. 2023 May 29;12(11):3743
5. Tiwari S et al. Amyand's Hernia: A Systematic Review of Clinical Presentations, Surgical Management, and Outcomes in an Uncommon Picture of a Common Entity. Cureus. 2025 Sep 16;17(9):e92416.
6. Vo P et al. De Garengeot’s hernia: A rare presentation of acute appendicitis and challenging preoperative diagnosis. Radiol Case Rep. 2026 Jul 4;21(10):4333–4337.
7. Kanani F et al. Systematic Review of Ischiatic Hernia: Diagnostic Challenges, Surgical Evolution, and Outcomes. Am Surg. 2026 Feb;92(2):609-618.