The iliohypogastric and ilioinguinal nerves. Distribution in the abdominal wall, danger areas in surgical incisions in the inguinal and pubic regions and reflected visceral pain in their dermatomes.

The courses of the iliohypogastric and ilioinguinal nerves were studied in 44 adult human cadavers, in order to clarify their relations to incisions in the abdominal wall in appendectomy, inguinal hernial repair, caesarean section and lumbar nephrectomy. If either of these nerves is trapped during suturing of the abdominal layers, especially after inguinal hernia repair and appendectomy typical nerve irritation in the inguinal region is observed. To avoid cutting the anterior branches of the iliohypogastric and ilioinguinal nerves in appendectomy, incisions should be placed at a distance of not less than 3 cm from the anterior superior iliac spine. In inguinal hernial repair, after the external oblique aponeurosis has been opened, the ilioinguinal nerve should be displaced from the spermatic cord cranially. In performing a lower paramedian incision (Lennander) and Pfannenstiel's suprapubic incision, the iliohypogastric nerve will be spared if the incision passes at least 5 cm cranial to the inguinal ligament. During oblique lumbar incision for nephrectomy (Bergmann-Israel) the iliohypogastric nerve can easily be found in the middle third of the lateral margin of the quadratus lumborum muscle. The nerve should be displaced carefully downwards. Positional changes of the kidney or ureter, perinephric inflammation, etc. are often referred to the skin areas (Head, Mackenzie) of the iliohypogastric and ilioinguinal nerves.