Anatomic pattern and variations of the ilioinguinal nerve as it travels throughout the anterior abdominal wall: Cadaveric study

Abstract

Introduction: Ilioinguinal nerve (IIN) is repeatedly damaged during surgeries as well as through the application of local anaesthesia to the lower abdominal wall. This study aimed to identify the variations of the IIN during its course in the anterior abdominal wall. Materials and Methods: A cross-sectional study on formalin-preserved cadavers was carried out after approval by the ethical committee, Alzaeim Alazhari University (January 2018–May 2020). Cadavers satisfied the inclusion criteria were dissected bilaterally to expose and map the IINs from their lateral emergence on the anterior abdominal wall to their termination in the midline in reference to the internal and external inguinal rings as well as the fixed bony landmarks. The collected data were compared on both sides using SPSS version 21.0. Results: Fifty-four IINs were identified (77 cadavers). Double nerve was observed in 8.44%. IINs derived from L1, L1-3 and L3 in 98.1%, 1.3% and 0.6%, respectively. On the right side, in 3 corpses, the nerves aberrantly ascend from L3 or L1-3, whereas this deviant was not seen on the left side. The mean distance from the umbilicus was 9.2 cm ± 1.1 cm (equal on both sides). The mean distance from the deep ring was 1.5 cm ± 0.4 cm, it was closed on the right compared to the left (P = 0.87). It emerges 0.9 cm–6 cm from the anterior superior iliac spine, this was closed on the right than the left (P = 0.9). It was not attached to the external oblique muscle on the right side, whereas it did in 3.2% on the left (P = 0.03). The mean distance from the superficial ring was 1.9 cm ± 0.8 cm, almost the same on both sides. The mean distance from the inguinal ligament was 2.4 cm ± 0.5 cm, it was closed on the right than on the left (P = 0.98). Its mean thickness was 1.97 mm ± 0.44 mm and 1.88 mm ± 0.43 mm on the right and left sides, respectively. Conclusion: IIN demarcates variants not generally quoted in anatomical manuals.