Arcuate line of the rectus sheath: clinical approach

The rectus sheath has been extensively described in gross anatomic studies but there is very little information available regarding the arcuate line (AL). The aim of the present study therefore was to explore and delineate the morphology, topography and morphometry of the arcuate line and provide a comprehensive picture of its anatomy across a broad range of specimens. The AL was present in all specimens examined. In addition, the AL was found to be located at a mean of 70.2% (67.3–75.2%) of the distance between the pubic symphysis and the umbilicus, and at 33.9% (30.2–35.4%) of the distance between the pubic symphysis and the xiphoid process. This location was found to be at a mean of 2.1 ± 2.3 cm superior to the level of the anterior superior iliac spines. Furthermore, there were three distinct types of AL morphology. In type I (65%), the fibers of the posterior rectus sheath (PRS) gradually disappeared over the transversalis fascia, creating an incomplete demarcation of the actual location of the AL. In type II (25%) the termination of the fibers of the PRS was acutely demarcated over the transversalis fascia, creating a clear border with the AL. In type III (10%) the fibers of the PRS created a double and thickened aponeurotic line. In these cases a double AL was observed. Better preoperative knowledge of the location of the AL may, in some cases, help preoperative planning to facilitate primary fascial repair, which can then be supported with on-lay mesh, depending on the clinical situation.