Back mice are related to cluneal nerve entrapment, but there are other entrapments that are worthy to study to better understand the peripheral neuropathies. The ilio-inguinal nerve entrapment is one of them.
The paper reports 4 case histories in which ilio-inguinal nerve entrapment has occurred in healthy YOUNG WOMEN. Two of them, because of acute intense pain, underwent extensive medical investigation (one even underwent surgical removal of a normal appendix). (Personal note: McSherry warns about this entity so, if unknown, the pain pattern can be erroneously ascribed to more SERIOUS pathologies such as appendicitis or salpingitis. Nevertheless, the ilioinguinal nerve can be entrapped in different parts of its nerve pathway as it crosses several muscular/fascial structures. McSherry presents 4 cases where the entrapment was in its fascial exit of the internal oblique muscle).
The cardinal clinical features of ilio-inguinal entrapment neuropathy are:
1- L1 dermatome pain
2- Typical single-finger pressure pain (trigger point) in the ilio-inguinal neuro-vascular foramen adjacent to the anterior superior iliac spine
The author says that the abdominal pain by this neuropathy may be more common than it is generally realized. Primary-care physicians’ knowledge may benefit some patients.
Long-standing neuropathy may result in denervation with an ultimate development of an indirect inguinal hernia.
The author is James McSherry, MB, ChB Director, Student Health Service Queen’s University, Kingston, Ontario. CANADA
Article free online
Personal notes on the article:
Ilio-inguinal Nerve Entrapment Syndrome: A Cause of Abdominal Pain
Canadian Family Physician. 1987; 33: 467-469.
From Ontario, Canada
The pathway of the ilio-inguinal nerve
The ilio-inguinal nerve is the continuation of the undivided primary ramus of the first lumbar root (L1).
It circles the trunk between the transverse and internal oblique muscles, runs through the internal and external oblique muscles below the medial to the anterior superior iliac spine and enters the inguinal canal.
The terminal branches of the ilio-inguinal nerve
It supplies the terminal branches of the inguinal region up top the iliac crest, the anterior abdominal wall overlying the symphysis pubis, the root and the dorsum of the penis or proximal part of the labia majora and a portion of the thigh medial to the femoral triangle.
Vulnerable sites of injury of the ilio-inguinal nerve
1-During inguinal herniorraphy from a section or from adhesions
2-In the fascial neurovascular foramen near the anterior superior iliac spine (by increased intra-abdominal pressure, abdominal muscle contraction and asphericity of the femoral heads).
Main ilio-inguinal nerve neuropathy symptoms
Mainly PAIN, localized or felt diffusely over the first lumbar dermatome
Exploration of the ilio-inguinal nerve
There can be an acute tender point (trigger point) at the exit of the nerve from the abdominal muscle near the anterior superior iliac spine usually adjacent to the lateral border of the rectus abdominis.
Differencial diagnosis of the ilio-inguinal nerve entrapemnt
The L1 distribution may lead to confusion. It can be ascribed to: appendicitis, urinary tract infection, renal stone, salpingitis, ovarian pathology, epididymo-orchitis, and other intra-abdominal pains.
Diagnostic confirmation: Ilio-inguinal nerve block
Local anesthetic injection into the area of maximum tenderness (the neuro-vascular foramina medial to the anterior superior iliac spine).
The injection should produce rapid temporary relief of pain, and then the condition may be treated by steroid injection, surgical release or phenol injection.
McSherry medical cases about ilio-inguinal nerve entrapment
A 24-year-old woman presented right-sided lower abdominal pain of less than 24 h duration. Continuous pain with accentuations caused by movement. Normal rest. The patient referred right iliac fossa tenderness, a point of ACUTE TENDERNESS located 2 cm medial to the anterior superior iliac spine. Pressure on that point produced pain medially towards the pubic area. Local injection of this point relieved the patient’s pain completely. Pain free during 2 years.
A 22-year-old woman right-lower-quadrant abdominal pain for 2 days. She had previous similar pains in 4 occasions within the previous eight months. All the investigations failed to give a reason for the pain, which subsided spontaneously over a few days of conservative treatment.
The patient described the pain as continuous ache with periodic stabbing burst. Abdominal palpation found tenderness in the lower-right iliac fossa without guarding or rebound tenderness. Rest of exploration normal.
There was a tender point that elicited radiating pain to the pubic area in the inguinal fold 2-3 cm medial to the anterior superior iliac spine. Local anesthetic injection gave immediate relief and the patient remained free of pain for several years.
A 23-year-old woman presented with severe right-sided lower abdominal pain of two days of duration. She had similar episodes in four occasions within the preceding six months. A normal appendix was removed during her first admission, and an ovarian cyst was diagnosed during her second episode. Then she started oral anticonception. Two more occasions subsided further investigations in hospital but it resolved spontaneously within a few days. On palpation, they found an exquisite tenderness point 2-3 cm medial to the anterior-superior iliac spine. On pressure there was radiation to pubic area. Local anesthesia relieved the pain immediately.
A 20-year-old woman presented mild lower-right-sided abdominal pain for 2 days. Previously, she had an inflammatory pelvic disease and she was afraid it was a relapse. She had been doing physical fitness the previous days. They found a tender spot 2-3 cm medial to the anterior iliac crest that injected with LA and gave immediate relief.
Published in September 2018 By Marta Cañis Parera
- McSherry J. Ilio-inguinal Nerve Entrapment Syndrome: A Cause of Abdominal Pain. Can Fam Physician. 1987 Feb; 33: 467-9. PubMed PMID: 21263838; PubMed CentralPMCID: PMC2218348.
- Kopell HP, Thompson WAL. Ilioinguinal nerve. Peripheral entrapment neuropathies. New York: Kreiger 1976, pp. 77-83.