[image: 1740662895953-1000039779.jpg]
What is the arcuate line?
The arcuate line, also known as the semicircular line of Douglas, is a curved line found posterior to the rectus abdominis muscle bilaterally, between the umbilicus and the pubic symphysis. This anatomical finding may not always be present, and its exact position may vary.
Superior to the arcuate line, the external oblique aponeurosis (i.e., a thin layer of connective tissue that covers and supports the muscle) passes anterior to the rectus abdominis muscle. The aponeurosis of the internal oblique splits to surround the rectus abdominis muscle. Additionally, posterior to the rectus abdominis muscle is the aponeurosis of the transversus abdominis muscle, as well as the transversalis fascia. All of the aforementioned aponeuroses wrap around the rectus abdominis muscle, forming the rectus sheath. At the level of and posteriorly to the arcuate line, the aponeuroses of the internal oblique and transversus abdominis pass anteriorly to the rectus abdominis muscle, instead of surrounding the muscle
@isurg@lemm.ee
