|The arcuate line is the arch-shaped (hence the name) inferior border of the posterior sheath of the rectus abdominis muscle. This structure is seen in a laparoscopic (posterior) view (see image, label "B") and represents the transition from a superior area with well-formed aponeurotic posterior rectus sheath to an area devoid of the posterior rectus sheath.
At this point, the inferior (deep) epigastric vessels (see image, label "C") pass from deep to superficial, under the arcuate line and continue superiorly providing blood to the rectus abdominis muscle.
The arcuate line also represents a transition from a well-formed and stronger wall posterior to the rectus abdominis muscle to a weaker region, covered only by deep muscle fascia and transversalis fascia. This allows a surgeon to enter the preperitoneal region using a Totally Extraperitoneal (TEP) approach for a laparoscopic herniorrhaphy.
Label "A" shows the "corona mortis" anatomical variation